commit 7b2650b64615517cc37952a59e31540a82150216
Author: Marcin Woźniak <y0rune@aol.com>
Date:   Mon Sep 14 11:00:29 2020 +0200

    Added
    
    Signed-off-by: Marcin Woźniak <y0rune@aol.com>

diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
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index 0000000..1362d41
--- /dev/null
+++ b/CONTRIBUTING.md
@@ -0,0 +1,57 @@
+Contributing
+============
+
+All kinds of contributions to Mons are greatly appreciated. For someone
+unfamiliar with the code base, the most efficient way to contribute is usually
+to submit a [feature request](#feature-requests) or [bug report](#bug-reports).
+If you want to dive into the source code, you can submit a [patch](#patches) as
+well, either working on your own ideas or [existing issues][issues].
+
+Feature Requests
+----------------
+
+Do you have an idea for an awesome new feature for Mons? Please [submit a
+feature request][issue]. It's great to hear about new ideas.
+
+If you are inclined to do so, you're welcome to [fork][fork] Mons, work on
+implementing the feature yourself, and submit a patch. In this case, it's
+*highly recommended* that you first [open an issue][issue] describing your
+enhancement to get early feedback on the new feature that you are implementing.
+This will help avoid wasted efforts and ensure that your work is incorporated
+into the code base.
+
+Bug Reports
+-----------
+
+Did something go wrong with Mons? Sorry about that! Bug reports are greatly
+appreciated!
+
+When you [submit a bug report][issue], please include relevant information such
+as Mons version, operating system, configuration file, error messages, and
+steps to reproduce the bug. The more details you can include, the easier it is
+to find and fix the bug.
+
+Patches
+-------
+
+If there are [open issues][issues], you're more than welcome to work on those -
+this is probably the best way to contribute to Mons. If you have your own
+ideas, that's great too! In that case, before working on substantial changes to
+the code base, it is *highly recommended* that you first [open an issue][issue]
+describing what you intend to work on.
+
+**Patches are generally submitted as pull requests.** Patches are also
+[accepted over email][email].
+
+The version history should be clean, and commit messages should be descriptive
+and [properly formatted][commit-messages].
+
+---
+
+If you have any questions about anything, feel free to [ask][email]!
+
+[issue]: https://github.com/ventto/mons/issues/new
+[issues]: https://github.com/ventto/mons/issues
+[fork]: https://github.com/ventto/mons/fork
+[email]: mailto:thomas.venries@gmail.com
+[commit-messages]: http://tbaggery.com/2008/04/19/a-note-about-git-commit-messages.html
diff --git a/LICENSE b/LICENSE
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--- /dev/null
+++ b/LICENSE
@@ -0,0 +1,20 @@
+The MIT License (MIT)
+
+Copyright (c) 2016-2017 Thomas "Ventto" Venriès <thomas.venries@gmail.com>
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of
+this software and associated documentation files (the "Software"), to deal in
+the Software without restriction, including without limitation the rights to
+use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+the Software, and to permit persons to whom the Software is furnished to do so,
+subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
+IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
diff --git a/Makefile b/Makefile
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--- /dev/null
+++ b/Makefile
@@ -0,0 +1,37 @@
+PKGNAME		= mons
+PKGDESC		= POSIX Shell script to quickly manage 2-monitors display.
+
+LICENSEDIR  = $(DESTDIR)/usr/share/licenses/$(PKGNAME)
+MANDIR		= $(DESTDIR)/usr/share/man/man1
+BINDIR  	= $(DESTDIR)/usr/bin
+LIBDIR  	= $(DESTDIR)/usr/lib/libshlist
+LIB     	= libshlist/liblist.sh
+
+install:
+	@if ! [ -r "$(LIB)" ]; then \
+		echo "$(LIB): missing file"; \
+		exit 1; \
+	fi
+	help2man -N -n "$(PKGDESC)" -h -h -v -v ./$(PKGNAME) | gzip - > $(PKGNAME).1.gz
+	@if ! [ -r "$(PKGNAME).1.gz" ]; then \
+		echo "$(PKGNAME).1.gz: missing manpage"; \
+		exit 1; \
+	fi
+	mkdir -p $(MANDIR)
+	mkdir -p $(LICENSEDIR)
+	mkdir -p $(LIBDIR)
+	mkdir -p $(BINDIR)
+	chmod 644 $(PKGNAME).1.gz
+	chmod 644 LICENSE
+	chmod 644 $(LIB)
+	chmod 755 mons
+	cp $(PKGNAME).1.gz $(MANDIR)/$(PKGNAME).1.gz
+	cp LICENSE $(LICENSEDIR)/LICENSE
+	cp $(LIB) $(LIBDIR)/liblist.sh
+	cp mons $(BINDIR)/mons
+
+uninstall:
+	$(RM) -r $(LIBDIR)
+	$(RM) $(BINDIR)/mons
+
+.PHONY: install uninstall
diff --git a/README.md b/README.md
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--- /dev/null
+++ b/README.md
@@ -0,0 +1,200 @@
+Mons
+===================
+[![License](https://img.shields.io/badge/license-MIT-blue.svg?style=flat)](https://github.com/Ventto/mons/blob/master/LICENSE)
+[![Language (XRandR)](https://img.shields.io/badge/powered_by-XRandR-brightgreen.svg)](https://www.x.org/archive/X11R7.5/doc/man/man1/xrandr.1.html)
+[![Vote for mons](https://img.shields.io/badge/AUR-Vote_for-yellow.svg)](https://aur.archlinux.org/packages/mons/)
+
+
+
+*"Mons is a Shell script to quickly manage 2-monitors display using xrandr."*
+
+## Perks
+
+* [x] **No requirement**: POSIX-compliant (minimal: *xorg-xrandr*)
+* [x] **Useful**: Perfectly fit for laptops, quick and daily use
+* [x] **Well known**: Laptop mode, projector mode, duplicate, mirror and extend
+* [x] **More**:  Select one or two monitors over several others
+* [x] **Extra**: Cycle through every mode with only one shortcut
+* [x] **Auto**: Deamon mode to automatically reset display
+
+# Installation
+
+* Package (AUR)
+
+```
+$ pacaur -S mons
+```
+
+* Manual
+
+```
+$ git clone --recursive https://github.com/Ventto/mons.git
+$ cd mons
+$ sudo make install
+```
+> Note: `--recursive` is needed for git submodule
+
+# Usage
+
+```
+Without argument, it prints connected monitors list with their names and ids.
+Options are exclusive and can be used in conjunction with extra options.
+
+Information:
+  -h    Prints this help and exits.
+  -v    Prints version and exits.
+
+Two monitors:
+  -o    Primary monitor only.
+  -s    Second monitor only.
+  -d    Duplicates the primary monitor.
+  -m    Mirrors the primary monitor.
+  -e <side>
+         Extends the primary monitor to the selected side
+         [ top | left | right | bottom ].
+  -n <side>
+         This mode selects the previous ones, one after another. The argument
+         sets the side for the extend mode.
+
+More monitors:
+  -O <mon>
+        Only enables the monitor with a specified id.
+  -S <mon1>,<mon2>:<pos>
+        Only enables two monitors with specified ids. The specified position
+        places the second monitor on the right (R) or at the top (T).
+
+Extra (in-conjunction options):
+  --dpi <dpi>
+        Set the DPI, a strictly positive value within the range [0 ; 27432].
+  --primary <mon_name>
+        Select a connected monitor as the primary output. Run the script
+        without argument to print monitors information, the names are in the
+        second column between ids and status. The primary monitor is marked
+        by an asterisk.
+
+Daemon mode:
+  -a    Performs an automatic display if it detects only one monitor.
+```
+
+# Examples
+
+## Two monitors
+
+Displays monitor list:
+
+```
+$ mons
+0: LVDS-1   (enabled)
+5: VGA-1
+```
+
+You have an enabled one, you want to extends the second one on the right:
+
+```
+$ mons -e right
+```
+
+You want to only display the second one:
+
+```
+$ mons -s
+```
+
+With the `-n` option, go through every 2-mons mode consecutively:
+
+1. Primary monitor only
+1. Second monitor only
+1. Extend mode whose the side is set with `-n <side>`
+1. Mirror
+1. Duplicate
+
+This mode is useful if you want to switch to every mode with only one shortcut.
+
+![alt 2-monitors modes](img/raw-body.png)
+
+```
+# Now in 'Second monitor mode'
+$ mons -n right # -> 'Extend mode'
+# Now in 'Extend mode'
+$ mons -n right # -> 'Mirror mode'
+```
+
+## Three monitors (selection mode)
+
+
+Displays monitor list:
+
+```
+$ mons
+Monitors: 3
+Mode: Selection
+0:* LVDS-1   (enabled)
+1: DP-1      (enabled)
+5: VGA-1
+```
+
+You may need to display only the third one:
+
+```
+$ mons -O 5
+```
+
+You may need to display the first and the third one on the right:
+
+```
+$ mons -S 0,5:R
+```
+
+Like above but you want to inverse the placement:
+
+```
+$ mons -S 5,0:R
+```
+
+## DPI value
+
+You might want to switch mode and set the DPI value.
+Use the `--dpi <dpi>` option in conjunction with all others options.
+
+```
+$ mons [OPTIONS] --dpi <dpi>
+```
+
+## Primary monitor
+
+You might choose one of your monitors as the main one.
+You can use the `--primary <mon_name>` option alone or in conjunction with all
+others options.
+`<mon_name>` refers to the monitor name that appears in the list of connected
+monitors (ex: `LVDS-1` or `VGA-1`):
+
+```
+$ mons
+Monitors: 3
+Mode: Primary
+0:* LVDS-1   (enabled)
+5:  VGA-1
+```
+
+The '*' character means that the monitor is the primary one:
+
+```
+$ mons --primary VGA-1
+Monitors: 3
+Mode: Primary
+0:  LVDS-1   (enabled)
+5:* VGA-1
+```
+
+## Daemon mode
+
+Especially for laptops, after unplugging the additional monitors, it might be
+convenient to reset automatically the display for the remaining one.
+
+Run *mons* in background as follow:
+
+```
+$ nohup mons -a > /dev/null 2>&1 &  (all shells)
+$ mons -a &!                        (zsh)
+$ mons -a &; disown                 (bash)
+```
diff --git a/_gitignore b/_gitignore
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+++ b/_gitignore
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+/*
+
+!libshlist
+
+!img
+img/*
+!img/raw-body.png
+
+!test
+test/*
+!test/*.sh
+
+!mons
+!CONTRIBUTING.md
+!LICENSE
+!Makefile
+!README.md
+!.gitignore
+!.gitmodules
diff --git a/_gitmodules b/_gitmodules
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index 0000000..136cc85
--- /dev/null
+++ b/_gitmodules
@@ -0,0 +1,3 @@
+[submodule "libshlist"]
+	path = libshlist
+	url = https://github.com/Ventto/libshlist.git
diff --git a/img/raw-body.png b/img/raw-body.png
new file mode 100644
index 0000000..0dfbb8d
Binary files /dev/null and b/img/raw-body.png differ
diff --git a/libshlist/LICENSE b/libshlist/LICENSE
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--- /dev/null
+++ b/libshlist/LICENSE
@@ -0,0 +1,20 @@
+The MIT License (MIT)
+
+Copyright (c) 2017-2018 Thomas "Ventto" Venriès <thomas.venries@gmail.com>
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of
+this software and associated documentation files (the "Software"), to deal in
+the Software without restriction, including without limitation the rights to
+use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+the Software, and to permit persons to whom the Software is furnished to do so,
+subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
+IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
diff --git a/libshlist/README.md b/libshlist/README.md
new file mode 100644
index 0000000..dd7f70a
--- /dev/null
+++ b/libshlist/README.md
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+POSIX Shell List
+================
+
+[![License](https://img.shields.io/badge/license-MIT-blue.svg?style=flat)](https://github.com/Ventto/posix-shell-list/blob/master/LICENSE)
+
+*"This is a POSIX Shell list implementation."*
+
+## Perks
+
+* [x] **No requirement**: POSIX-compliant
+* [x] **Lightweight**: ~100 lines
+* [x] **Extra**: Additional functions to fit your needs
+* [x] **Useful**: No internal independency
+* [x] **Both**: Safe and unsafe (passing argument by reference) versions
+
+# Installation
+
+* Download it:
+
+```bash
+$ wget https://raw.githubusercontent.com/Ventto/posix-shell-list/master/liblist.sh
+```
+
+* Source the library for including the functions into your Shell script:
+
+```bash
+. liblist.sh  (or)
+. liblist_unsafe.sh
+```
+
+* Each function is independent. So you can copy some functions into your
+script without sourcing
+
+# Functions
+
+The whole function documentation is in the following library scripts:
+
+* `liblist.sh`: the variable assignation is required for conserving changes
+* `liblist_unsafe.sh`: uses `eval` special shell builtin for passing argument
+   by reference and set the list variable
+
+The following list enumerates all available functions:
+
+```
+                SAFE                |           UNSAFE
+____________________________________|_______________________________
+list <elt> <elt> ...                |  list <elt> <elt> ...
+list_back <lst>                     |  list_back <lst>
+list_contains <elt> <lst>           |  list_contains <lst> <elt>
+list_count <elt> <lst>              |  list_count <lst> <elt>
+list_empty <lst>                    |  list_empty <lst>
+list_erase <elt> <lst>              |  list_erase <lst> <elt>
+list_erase_from <index> <lst>       |  list_erase_from <lst> <index>
+list_erase_range <from> <to> <lst>  |  list_erase_range <lst> <from> <to>
+list_eraseat <index> <lst>          |  list_eraseat <lst> <index>
+list_extract <from> <to> <lst>      |  list_extract <lst> <from> <to>
+list_front <lst>                    |  list_front <lst>
+list_get <index> <lst>              |  list_get <lst> <index>
+list_indexof <elt> <lst>            |  list_indexof <lst> <elt>
+list_insert <elt> <index> <lst>     |  list_insert <lst> <elt> <index>
+list_maps <func> <lst>              |  list_maps <lst> <func>
+list_pop_back <lst>                 |  list_pop_back <lst>
+list_pop_front <lst>                |  list_pop_front <lst>
+list_push_back <elt> <lst>          |  list_push_back <lst> <elt>
+list_push_front <elt> <lst>         |  list_push_front <lst> <elt>
+list_remove <elt> <lst>             |  list_remove <lst> <elt>
+list_replace <new> <old> <lst>      |  list_replace <lst> <new> <old>
+list_reverse <lst>                  |  list_reverse <lst>
+list_set <elt> <index> <lst>        |  list_set <lst> <elt> <index>
+list_size <lst>                     |  list_size <lst>
+list_sort <lst>                     |  list_sort <lst>
+list_sort_reverse <lst>             |  list_sort_reverse <lst>
+```
+
+# Example
+
+Scripts in `test/` offer an exhaustive usage of both libraries.
+
+* Quick start (safe version):
+
+```bash
+lst="$(list 'A' 'B' 'C')"
+lst="$(list_sort "$lst")"           # { C, B, A }
+
+if list_empty "$lst"; then
+    echo 'The list is empty.'
+fi
+
+index="$(list_indexof 'D' "$lst")"  # '', empty string
+
+if [ "$?" -ne 0 ]; then
+    echo 'Element not found.'
+fi
+```
+
+* Quick start (unsafe version):
+
+```bash
+lst="$(list 'A' 'B' 'C')"
+list_sort lst                    # { C, B, A }
+
+if list_empty lst; then
+    echo 'The list is empty.'
+fi
+
+index="$(list_indexof lst 'D')"  # '', empty string
+
+if [ "$?" -ne 0 ]; then
+    echo 'Element not found.'
+fi
+```
diff --git a/libshlist/_git b/libshlist/_git
new file mode 100644
index 0000000..6e67b0c
--- /dev/null
+++ b/libshlist/_git
@@ -0,0 +1 @@
+gitdir: ../.git/modules/libshlist
diff --git a/libshlist/liblist.sh b/libshlist/liblist.sh
new file mode 100644
index 0000000..d3a2144
--- /dev/null
+++ b/libshlist/liblist.sh
@@ -0,0 +1,271 @@
+#!/bin/sh
+#
+# The MIT License (MIT)
+#
+# Copyright (c) 2017-2018 Thomas "Ventto" Venriès <thomas.venries@gmail.com>
+#
+# Permission is hereby granted, free of charge, to any person obtaining a copy of
+# this software and associated documentation files (the "Software"), to deal in
+# the Software without restriction, including without limitation the rights to
+# use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+# the Software, and to permit persons to whom the Software is furnished to do so,
+# subject to the following conditions:
+#
+# The above copyright notice and this permission notice shall be included in all
+# copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+# FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+# COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
+# IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+# CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+##
+# @brief    Return a list from argument strings
+# @usage    list <elt> <elt> ...
+# @print    The created list
+#
+list () {
+    for e; do [ -n "$e" ] && echo "$e"; done
+}
+
+##
+# @brief    Prints the number of elements in the list
+# @usage    list_size <lst>
+# @print    The size of the list as positive integer
+#
+list_size () {
+    if [ -z "$1" ]; then echo '0'; else echo "$@" | wc -l; fi
+}
+
+##
+# @brief    Returns whether the list is empty(1) or not(0)
+# @usage    list_empty <lst>
+# @return   The exit code of the command
+#
+list_empty () {
+    test -z "$1"
+}
+
+##
+# @brief    Adds a new element at the beginning of the list
+# @usage    list_push_front <elt> <lst>
+# @print    The list result
+#
+list_push_front () {
+    test "$#" -ne 2 && return 1
+    if [ "$2" = '' ]; then echo "$1"; else printf '%s\n%s' "$1" "$2"; fi
+}
+
+##
+# @brief    Adds a new element at the end of the list
+# @usage    list_push_back <elt> <lst>
+# @print    The list result
+#
+list_push_back () {
+    test "$#" -ne 2 && return 1
+    if [ "$2" = '' ]; then echo "$1"; else printf '%s\n%s' "$2" "$1"; fi
+}
+
+##
+# @brief    Inserts new elements in the list before a specified position
+# @usage    list_insert <elt> <index> <lst>
+# @print    The list result
+#
+list_insert () {
+    test "$#" -ne 3 && return 1
+    i="$2"; [ "$i" != '$' ] &&  i=$((i+1)); echo "$3" | sed "${i}i${1}"
+}
+
+##
+# @brief    Modifies an element from the list at a specified position
+# @usage    list_set <elt> <index> <lst>
+# @print    The list result
+#
+list_set () {
+    test "$#" -ne 3 && return 1
+    i="$2"; i=$((i+1)); echo "$3" | sed -e "${i}s/.*/$1/"
+}
+
+##
+# @brief    Extracts a range of elements from the list between two specified
+#           positions
+# @usage    list_extract <from_index> <to_index> <lst>
+# @print    The list result
+#
+list_extract () {
+    test "$#" -ne 3 && return 1
+    i="$1"; j="$2"; i=$((i+1)); j=$((j+1)); echo "$3" | sed -n "${i},${j}p"
+}
+
+##
+# @brief    Replaces all elements from the list with a specified element
+# @usage    list_replace <new_elt> <old_elt> <lst>
+# @print    The list result
+#
+list_replace () {
+    test "$#" -ne 3 && return 1; echo "$3" | sed -e "s/^$1$/$2/g"
+}
+
+##
+# @brief    Prints the element at a specified position
+# @usage    list_get <index> <lst>
+# @print    The element found
+#
+list_get () {
+    test "$#" -ne 2 && return 1; i="$1"; i=$((i+1)); echo "$2" | sed -n "${i}p"
+}
+
+##
+# @brief    Prints the head of the list
+# @usage    list_front <lst>
+# @print    The element found
+#
+list_front () {
+    test "$#" -ne 1 && return 1; echo "$@" | sed -n '1p'
+}
+
+##
+# @brief    Prints the queue of the list
+# @usage    list_back <lst>
+# @print    The element found
+#
+list_back () {
+    test "$#" -ne 1 && return 1; echo "$@" | sed -n '$p'
+}
+
+##
+# @brief    Removes the first-hit element from a list
+# @usage    list_erase <elt> <lst>
+# @print    The list result
+#
+list_erase () {
+    test "$#" -ne 2 && return 1; echo "$2" | sed -e "0,/^$1$/ s///" -e '/^$/d'
+}
+
+##
+# @brief    Removes a range of elements from a list between two specified
+#           positions
+# @usage    list_erase_range <from_index> <to_index> <lst>
+# @print    The list result
+#
+list_erase_range () {
+    test "$#" -ne 3 && return 1
+    i="$1"; j="$2"; i=$((i+1)); j=$((j+1)); echo "$3" | sed "${i},${j}d"
+}
+
+##
+# @brief    Removes all elements from a specified position
+# @usage    list_erase_from <index> <lst>
+# @print    The list result
+#
+list_erase_from () {
+    test "$#" -ne 2 && return 1; i="$1"; i=$((i+1)); echo "$2" | sed "${i},\$d"
+}
+
+##
+# @brief    Removes the element at a specified position
+# @usage    list_eraseat <index> <lst>
+# @print    The list result
+#
+list_eraseat () {
+    test "$#" -ne 2 && return 1; i="$1"; i=$((i+1)); echo "$2" | sed "${i}d"
+}
+
+##
+# @brief    Removes all the elements from the list, which are equal to given
+#           element
+# @usage    list_remove <elt> <lst>
+# @print    The list result
+#
+list_remove () {
+    test "$#" -ne 2 && return 1; echo "$2" | sed -e "/^$1$/d"
+}
+
+##
+# @brief    Removes the first element of the list
+# @usage    list_pop_front <lst>
+# @print    The list result
+#
+list_pop_front () {
+    test "$#" -ne 1 && return 1; echo "$1" | sed '1d'
+}
+
+##
+# @brief    Removes the last element of the list
+# @usage    list_pop_back <lst>
+# @print    The list result
+#
+list_pop_back () {
+    test "$#" -ne 1 && return 1; echo "$1" | sed '$d'
+}
+
+##
+# @brief    Prints the index of a specified element
+# @usage    list_indexof <elt> <lst>
+# @print    The index or empty string if the element is not found
+#
+list_indexof () {
+    test "$#" -ne 2 && return 1; i=0
+    for e in $2; do
+        [ "$e" = "$1" ] && { echo "$i"; return 0; }; i=$((i+1));
+    done
+    return 1
+}
+
+##
+# @brief    Returns whether the list contains a specified element(0) or not(1)
+# @usage    list_contains <elt> <lst>
+# @return   0 or 1
+#
+list_contains () {
+    test "$#" -ne 2 && return 1
+    for e in $2; do [ "$e" = "$1" ] && return 0; done; return 1
+}
+
+##
+# @brief    Counts the number of a specified element in the list
+# @usage    list_count <elt> <lst>
+# @print    The number of elements as positive integer
+#
+list_count () {
+    test "$#" -ne 2 && return 1
+    i=0; for e in $2; do [ "$e" = "$1" ] && { i=$((i+1)); }; done; echo "$i"
+}
+
+##
+# @brief    Maps every element of the list
+# @usage    list_maps <func> <lst>
+# @print    The list result
+#
+list_map () {
+    test "$#" -ne 2 && return 1; for e in $2; do eval "$1 $e"; done
+}
+
+##
+# @brief    Reverses the list
+# @usage    list_reverse <lst>
+# @print    The list result
+#
+list_reverse() {
+    test "$#" -ne 1 && return 1; echo "$1" | sed '1!x;H;1h;$!d;g'
+}
+
+##
+# @brief    Sorts the list
+# @usage    list_sort <lst>
+# @print    The list result
+#
+list_sort () {
+    test "$#" -ne 1 && return 1; echo "$1" | sort -n
+}
+
+##
+# @brief    Sorts and reverses the sense of the list
+# @usage    list_sort_reverse <lst>
+# @print    The list result
+#
+list_sort_reverse () {
+    test "$#" -ne 1 && return 1; echo "$1" | sort -nr
+}
diff --git a/libshlist/liblist_unsafe.sh b/libshlist/liblist_unsafe.sh
new file mode 100644
index 0000000..af2625d
--- /dev/null
+++ b/libshlist/liblist_unsafe.sh
@@ -0,0 +1,286 @@
+#!/bin/sh
+#
+# The MIT License (MIT)
+#
+# Copyright (c) 2017-2018 Thomas "Ventto" Venriès <thomas.venries@gmail.com>
+#
+# Permission is hereby granted, free of charge, to any person obtaining a copy of
+# this software and associated documentation files (the "Software"), to deal in
+# the Software without restriction, including without limitation the rights to
+# use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+# the Software, and to permit persons to whom the Software is furnished to do so,
+# subject to the following conditions:
+#
+# The above copyright notice and this permission notice shall be included in all
+# copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+# FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+# COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
+# IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+# CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+##
+# @brief    Prints a list from arguments
+# @usage    list <elt> <elt> ...
+# @print    The list result
+#
+list () {
+    for e; do [ -n "$e" ] && echo "$e"; done
+}
+
+##
+# @brief    Prints the number of elements in the list
+# @usage    list_size <lst>
+# @print    The size of the list as positive integer
+#
+list_size () {
+    test "$#" -ne 1 && { echo "0"; return; }
+    eval "test -n \"\$$1\"" && { eval "echo \"\$$1\" | wc -l"; return; }
+    echo '0'
+}
+
+##
+# @brief    Returns whether the list is empty(1) or not(0)
+# @usage    list_empty <lst>
+# @return   0 or 1
+#
+list_empty () {
+    eval "test -z \"\$$1\""
+}
+
+##
+# @brief    Adds a new element at the beginning of the list
+# @usage    list_push_front <lst> <elt>
+# @out      Set the variable passed by reference
+#
+list_push_front () {
+    test "$#" -ne 2 && return 1
+    eval "test -n \"\$$1\"" || { eval "$1='$2'"; return; }
+    eval "$1=\"\$(printf '%s\n%s' '$2' \"\$$1\")\"";
+}
+
+##
+# @brief    Adds a new element at the end of the list
+# @usage    list_push_back <lst> <elt>
+# @out      Set the variable passed by reference
+#
+list_push_back () {
+    test "$#" -ne 2 && return 1
+    eval "test -n \"\$$1\"" || { eval "$1='$2'"; return; }
+    eval "test -n \"\$$1\"" || { eval "$1='$2'"; return; }
+    eval "$1=\"\$(printf '%s\n%s' \"\$$1\" '$2')\"";
+}
+
+##
+# @brief    Inserts new elements in the list before a specified position
+# @usage    list_insert <lst> <elt> <index>
+# @out      Set the variable passed by reference
+#
+list_insert () {
+    test "$#" -ne 3 && return 1; i="$3"; [ "$i" != '$' ] &&  i=$((i+1))
+    eval "$1=\"\$(echo \"\$$1\" | sed \"${i}i${2}\")\""
+}
+
+##
+# @brief    Modifies an element from the list at a specified position
+# @usage    list_set <lst> <elt> <index>
+# @out      Set the variable passed by reference
+#
+list_set () {
+    test "$#" -ne 3 && return 1
+    i="$3"; i=$((i+1)); eval "$1=\"\$(echo \"\$$1\" | sed \"${i}s/.*/$2/\")\""
+}
+
+##
+# @brief    Extracts a range of elements from the list between two specified
+#           positions
+# @usage    list_extract <lst> <from_index> <to_index>
+# @out      Set the variable passed by reference
+#
+list_extract () {
+    test "$#" -ne 3 && return 1; i="$2"; j="$3"; i=$((i+1)); j=$((j+1))
+    eval "$1=\"\$(echo \"\$$1\" | sed -n \"${i},${j}p\")\""
+}
+
+##
+# @brief    Replaces all elements from the list with a specified element
+# @usage    list_replace <lst> <old_elt> <new_elt>
+# @out      Set the variable passed by reference
+#
+list_replace () {
+    test "$#" -ne 3 && return 1
+    eval "$1=\"\$(echo \"\$$1\" | sed -e \"s/^$2$/$3/g\")\""
+}
+
+##
+# @brief    Prints the element at a specified position
+# @usage    list_get <lst> <index>
+# @print    The element found
+#
+list_get () {
+    test "$#" -ne 2 && return 1; i="$2"; i=$((i+1));
+    eval "echo \"\$$1\" | sed -n \"${i}p\""
+}
+
+##
+# @brief    Prints the head of the list
+# @usage    list_front <lst>
+# @print    The element found
+#
+list_front () {
+    test "$#" -ne 1 && return 1; eval "echo \"\$$1\" | sed -n '1p'"
+}
+
+##
+# @brief    Prints the queue of the list
+# @usage    list_back <lst>
+# @print    The element found
+#
+list_back () {
+    test "$#" -ne 1 && return 1; eval "echo \"\$$1\" | sed -n '\$p'"
+}
+
+##
+# @brief    Removes the first-hit element from a list
+# @usage    list_erase <lst> <elt>
+# @out      Set the variable passed by reference
+#
+list_erase () {
+    test "$#" -ne 2 && return 1
+    eval "$1=\"\$(echo \"\$$1\" | sed -e \"0,/^$2$/ s///\" -e '/^$/d')\""
+}
+
+##
+# @brief    Removes a range of elements from a list between two specified
+#           positions
+# @usage    list_erase_range <lst> <from_index> <to_index>
+# @out      Set the variable passed by reference
+#
+list_erase_range () {
+    test "$#" -ne 3 && return 1
+    i="$2"; j="$3"; i=$((i+1)); j=$((j+1));
+    eval "$1=\"\$(echo \"\$$1\" | sed \"${i},${j}d\")\""
+}
+
+##
+# @brief    Removes all elements from a specified position
+# @usage    list_erase_from <lst> <index>
+# @out      Set the variable passed by reference
+#
+list_erase_from () {
+    test "$#" -ne 2 && return 1
+    i="$2"; i=$((i+1)); eval "$1=\"\$(echo \"\$$1\" | sed \"${i},\\\$d\")\""
+}
+
+##
+# @brief    Removes the element at a specified position
+# @usage    list_eraseat <lst> <index>
+# @out      Set the variable passed by reference
+#
+list_eraseat () {
+    test "$#" -ne 2 && return 1
+    i="$2"; i=$((i+1)); eval "$1=\"\$(echo \"\$$1\" | sed \"${i}d\")\""
+}
+
+##
+# @brief    Removes all the elements from the list, which are equal to given
+#           element
+# @usage    list_remove <lst> <elt>
+# @out      Set the variable passed by reference
+#
+list_remove () {
+    test "$#" -ne 2 && return 1
+    eval "$1=\"\$(echo \"\$$1\" | sed -e \"/^$2$/d\")\""
+}
+
+##
+# @brief    Removes the first element of the list
+# @usage    list_pop_front <lst>
+# @out      Set the variable passed by reference
+#
+list_pop_front () {
+    test "$#" -ne 1 && return 1; eval "$1=\"\$(echo \"\$$1\" | sed '1d')\""
+}
+
+##
+# @brief    Removes the last element of the list
+# @usage    list_pop_back <lst>
+# @out      Set the variable passed by reference
+#
+list_pop_back () {
+    test "$#" -ne 1 && return 1; eval "$1=\"\$(echo \"\$$1\" | sed '\$d')\""
+}
+
+##
+# @brief    Prints the index of a specified element
+# @usage    list_indexof <lst> <elt>
+# @print    positive integer or -1 if not found
+#
+list_indexof () {
+    test "$#" -ne 2 && return 1; i=0
+    eval "for e in \$$1; do
+              [ \"\$e\" = '$2' ] && { echo \"\$i\"; return 0; }; i=\$((i+1));
+          done"
+    return 1
+}
+
+##
+# @brief    Returns whether the list contains a specified element(0) or not(1)
+# @usage    list_contains <lst> <elt>
+# @return   0 or 1
+#
+list_contains () {
+    test "$#" -ne 2 && return 1
+    eval "for e in \$$1; do [ \"\$e\" = '$2' ] && return 0; done; return 1"
+}
+
+##
+# @brief    Prints the number of a specified element in the list
+# @usage    list_count <lst> <elt>
+# @print    The number of elements as positive integer
+#
+list_count () {
+    test "$#" -ne 2 && { echo '0'; return; }
+    eval "i=0; for e in \$$1; do [ \"\$e\" = '$2' ] && { i=\$((i+1)); };done;"
+    echo "$i"
+}
+
+##
+# @brief    Maps every element of the list
+# @usage    list_maps <lst> <func>
+# @out      Set the variable passed by reference
+#
+list_map () {
+    test "$#" -ne 2 && return 1
+    eval "$1=\"\$(for e in \$$1; do eval \"$2 \$e\"; done)\""
+}
+
+##
+# @brief    Reverses the list
+# @usage    list_reverse <lst>
+# @out      Set the variable passed by reference
+#
+list_reverse() {
+    test "$#" -ne 1 && return 1
+    eval "$1=\"\$(echo \"\$$1\" | sed '1!x;H;1h;\$!d;g')\""
+}
+
+##
+# @brief    Sorts the list
+# @usage    list_sort <lst>
+# @out      Set the variable passed by reference
+#
+list_sort () {
+    test "$#" -ne 1 && return 1; eval "$1=\"\$(echo \"\$$1\" | sort -n)\""
+}
+
+##
+# @brief    Sorts and reverses the sense of the list
+# @usage    list_sort_reverse <lst>
+# @out      Set the variable passed by reference
+#
+list_sort_reverse () {
+    test "$#" -ne 1 && return 1; eval "$1=\"\$(echo \"\$$1\" | sort -nr)\""
+}
diff --git a/libshlist/test/test.sh b/libshlist/test/test.sh
new file mode 100644
index 0000000..c08334c
--- /dev/null
+++ b/libshlist/test/test.sh
@@ -0,0 +1,85 @@
+#!/bin/sh
+
+. ./liblist.sh
+
+print_list () {
+    echo '==========List============'
+    printf "%s\n" "$1"
+    echo '--------------------------'
+    printf "Size: %s\t\n\n" "$(list_size "$1")"
+}
+
+Test_Delete () {
+    lst="$(list '1'     '12'    '23'    \
+                '33'    '215'   '-456'  \
+                '1236'  '1'     '12'    \
+                '3'     '-3'    '33'    \
+                '1'     '12'    '-55'   \
+                '123'   '-1002' '-1'   )"
+
+    printf "TEST: Deletion\n\n"
+    echo 'test: Initialization'; print_list "$lst"
+
+    lst="$(list_remove '1' "$lst")"         ; echo 'test:' ; print_list "$lst"
+    lst="$(list_erase '33' "$lst")"         ; echo 'test:' ; print_list "$lst"
+    lst="$(list_eraseat '3' "$lst")"        ; echo 'test:' ; print_list "$lst"
+    lst="$(list_pop_front "$lst")"          ; echo 'test:' ; print_list "$lst"
+    lst="$(list_pop_back "$lst")"           ; echo 'test:' ; print_list "$lst"
+    lst="$(list_erase_from '8' "$lst")"     ; echo 'test:' ; print_list "$lst"
+    lst="$(list_erase_range '1' '2' "$lst")"; echo 'test:' ; print_list "$lst"
+    lst="$(list_erase_range '0' '0' "$lst")"; echo 'test:' ; print_list "$lst"
+    lst="$(list_extract '1' '3' "$lst")"    ; echo 'test:' ; print_list "$lst"
+    lst="$(list_extract '1' '30' "$lst")"   ; echo 'test:' ; print_list "$lst"
+    lst="$(list_extract '1' '0' "$lst")"    ; echo 'test:' ; print_list "$lst"
+}
+
+Test_Addition () {
+    lst=
+
+    printf "TEST: Addition\n\n"
+    echo 'test: Initialization'; print_list "$lst"
+
+    lst="$(list_push_front '12' "$lst")"    ; echo 'test:' ; print_list "$lst"
+    lst="$(list_push_back '33' "$lst")"     ; echo 'test:' ; print_list "$lst"
+    lst="$(list_push_front '1' "$lst")"     ; echo 'test:' ; print_list "$lst"
+    lst="$(list_insert '23' '2' "$lst")"    ; echo 'test:' ; print_list "$lst"
+    lst="$(list_push_back '215' "$lst")"    ; echo 'test:' ; print_list "$lst"
+}
+
+inc () { i="$1"; i=$((i+1)); echo "${i}"; }
+Test_Set() {
+    lst="$(list '1'     '12'    '23'    \
+                '33'    '215'   '-456'  \
+                '1236'  '1'     '12'    )"
+
+    printf "TEST: Set\n\n"
+    echo 'test: Initialization'; print_list "$lst"
+
+    lst="$(list_reverse "$lst")"            ; echo 'test:' ; print_list "$lst"
+    lst="$(list_sort "$lst")"               ; echo 'test:' ; print_list "$lst"
+    lst="$(list_sort_reverse "$lst")"       ; echo 'test:' ; print_list "$lst"
+    lst="$(list_map inc "$lst")"            ; echo 'test:' ; print_list "$lst"
+    lst="$(list_replace '2' '999' "$lst")"  ; echo 'test:' ; print_list "$lst"
+    lst="$(list_set '999' '3' "$lst")"      ; echo 'test:' ; print_list "$lst"
+    lst="$(list_set '999' '6' "$lst")"      ; echo 'test:' ; print_list "$lst"
+}
+
+Test_Get() {
+    lst="$(list '1'     '12'    '23'    \
+                '33'    '215'   '-456'  \
+                '1236'  '1'     '12'    )"
+
+    printf "TEST: Get\n\n"
+    echo 'test: Initialization'; print_list "$lst"
+
+    printf 'test: elt='     ; list_front "$lst"
+    printf 'test: elt='     ; list_back "$lst"
+    printf 'test: elt='     ; list_get '2' "$lst"
+    printf 'test: index='   ; list_indexof '1' "$lst" | grep -E '^[0-9]+$' || echo
+    printf 'test: index='   ; list_indexof '-456' "$lst" | grep -E '^[0-9]+$' || echo
+    printf 'test: contains='; list_contains '1236' "$lst" && echo 'yes' || echo 'no'
+    printf 'test: contains='; list_contains '999' "$lst" && echo 'yes' || echo 'no'
+    printf 'test: count='   ; list_count '1' "$lst"
+    printf 'test: count='   ; list_count '215' "$lst"
+    printf 'test: empty='   ; list_empty "$lst" && echo 'yes' || echo 'no'
+}
diff --git a/libshlist/test/test_unsafe.sh b/libshlist/test/test_unsafe.sh
new file mode 100644
index 0000000..f0f1920
--- /dev/null
+++ b/libshlist/test/test_unsafe.sh
@@ -0,0 +1,210 @@
+#!/bin/sh
+
+. ./liblist_unsafe.sh
+
+print_list () {
+    echo '==========List============'
+    eval "printf \"%s\\n\" \"\$$1\""
+    echo '--------------------------'
+    eval "printf \"Size: %s\t\n\n\" \"\$(list_size $1)\""
+}
+
+Test_Delete () {
+    lst="$(list '1'     '12'    '23'    \
+                '33'    '215'   '-456'  \
+                '1236'  '1'     '12'    \
+                '3'     '-3'    '33'    \
+                '1'     '12'    '-55'   \
+                '123'   '-1002' '-1'   )"
+
+    printf "TEST: Deletion\n\n"
+    echo 'test: Initialization'; print_list lst
+
+    list_remove lst '1'         ; echo 'test:' ; print_list lst
+    list_erase lst '33'         ; echo 'test:' ; print_list lst
+    list_eraseat lst 3          ; echo 'test:' ; print_list lst
+    list_pop_front lst          ; echo 'test:' ; print_list lst
+    list_pop_back lst           ; echo 'test:' ; print_list lst
+    list_erase_from lst 8       ; echo 'test:' ; print_list lst
+    list_erase_range lst 1 2    ; echo 'test:' ; print_list lst
+    list_erase_range lst 0 0    ; echo 'test:' ; print_list lst
+    list_extract lst 1 3        ; echo 'test:' ; print_list lst
+    list_extract lst 1 30       ; echo 'test:' ; print_list lst
+    list_extract lst 1 0        ; echo 'test:' ; print_list lst
+}
+
+Test_Addition () {
+    lst=
+
+    printf "TEST: Addition\n\n"
+    echo 'test: Initialization'; print_list lst
+
+    list_push_front lst '12'    ; echo 'test:' ; print_list lst
+    list_push_back lst '33'     ; echo 'test:' ; print_list lst
+    list_push_front lst '1'     ; echo 'test:' ; print_list lst
+    list_insert lst '23' 2      ; echo 'test:' ; print_list lst
+    list_push_back lst '215'    ; echo 'test:' ; print_list lst
+}
+
+inc () { i="$1"; i=$((i+1)); echo "${i}"; }
+Test_Set() {
+    lst="$(list '1'     '12'    '23'    \
+                '33'    '215'   '-456'  \
+                '1236'  '1'     '12'    )"
+
+    printf "TEST: Set\n\n"
+    echo 'test: Initialization'; print_list lst
+
+    list_reverse lst            ; echo 'test:' ; print_list lst
+    list_sort lst               ; echo 'test:' ; print_list lst
+    list_sort_reverse lst       ; echo 'test:' ; print_list lst
+    list_map lst inc            ; echo 'test:' ; print_list lst
+    list_replace lst '2' '999'  ; echo 'test:' ; print_list lst
+    list_set lst '999' 3        ; echo 'test:' ; print_list lst
+    list_set lst '999' 6        ; echo 'test:' ; print_list lst
+}
+
+Test_Get() {
+    lst="$(list '1'     '12'    '23'    \
+                '33'    '215'   '-456'  \
+                '1236'  '1'     '12'    )"
+
+    printf "TEST: Set\n\n"
+    echo 'test: Initialization'; print_list lst
+
+    printf 'test: elt='     ; list_front lst
+    printf 'test: elt='     ; list_back lst
+    printf 'test: elt='     ; list_get lst 2
+    printf 'test: index='   ; list_indexof lst '1'      | grep -E '^[0-9]+$' || echo
+    printf 'test: index='   ; list_indexof lst '-456'   | grep -E '^[0-9]+$' || echo
+    printf 'test: contains='; list_contains lst '1236'  && echo 'yes' || echo 'no'
+    printf 'test: contains='; list_contains lst '2'   && echo 'yes' || echo 'no'
+    printf 'test: count='   ; list_count lst '1'
+    printf 'test: count='   ; list_count lst '215'
+    printf 'test: empty='   ; list_empty lst && echo 'yes' || echo 'no'
+}
+
+Test_Void() {
+    lst="$(list '' '' '')"
+
+    printf "TEST: Void\n\n"
+    echo 'test: Initialization'; print_list lst
+
+    printf 'test (void): empty=' ; list_empty lst && echo 'yes' || echo 'no'
+    printf 'test (void): size='  ; list_size lst
+
+    list_reverse lst            ; echo 'test:' ; print_list lst
+    list_sort lst               ; echo 'test:' ; print_list lst
+    list_sort_reverse lst       ; echo 'test:' ; print_list lst
+    list_replace lst '2' '999'  ; echo 'test:' ; print_list lst
+    list_set lst '999' 3        ; echo 'test:' ; print_list lst
+    list_set lst '999' 6        ; echo 'test:' ; print_list lst
+    list_map lst inc            ; echo 'test:' ; print_list lst
+    list_remove lst '1'         ; echo 'test:' ; print_list lst
+    list_erase lst '33'         ; echo 'test:' ; print_list lst
+    list_eraseat lst 3          ; echo 'test:' ; print_list lst
+    list_pop_front lst          ; echo 'test:' ; print_list lst
+    list_pop_back lst           ; echo 'test:' ; print_list lst
+    list_erase_from lst 8       ; echo 'test:' ; print_list lst
+    list_erase_range lst 1 2    ; echo 'test:' ; print_list lst
+    list_erase_range lst 0 0    ; echo 'test:' ; print_list lst
+    list_extract lst 1 3        ; echo 'test:' ; print_list lst
+    list_extract lst 1 30       ; echo 'test:' ; print_list lst
+    list_extract lst 1 0        ; echo 'test:' ; print_list lst
+    list_push_front lst '2'     ; echo 'test:' ; print_list lst
+    list_push_back lst '4'      ; echo 'test:' ; print_list lst
+    list_push_front lst '1'     ; echo 'test:' ; print_list lst
+    list_insert lst '3' 2       ; echo 'test:' ; print_list lst
+    list_push_back lst '5'      ; echo 'test:' ; print_list lst
+}
+
+Test_BadArg() {
+    lst="$1"
+    printf "TEST: BadArg\n\n"
+    echo 'test: Initialization'; print_list lst
+
+    list_push_front lst     ; echo 'test:' ; print_list lst
+    list_push_front  ''     ; echo 'test:' ; print_list lst
+    list_push_front         ; echo 'test:' ; print_list lst
+
+    list_push_back lst      ; echo 'test:' ; print_list lst
+    list_push_back ''       ; echo 'test:' ; print_list lst
+    list_push_back          ; echo 'test:' ; print_list lst
+
+    list_insert lst ''      ; echo 'test:' ; print_list lst
+    list_insert lst         ; echo 'test:' ; print_list lst
+    list_insert 2           ; echo 'test:' ; print_list lst
+
+    list_reverse            ; echo 'test:' ; print_list lst
+    list_sort               ; echo 'test:' ; print_list lst
+    list_sort_reverse       ; echo 'test:' ; print_list lst
+
+    list_replace lst '2'    ; echo 'test:' ; print_list lst
+    list_replace lst        ; echo 'test:' ; print_list lst
+    list_replace            ; echo 'test:' ; print_list lst
+
+    list_set lst '999'      ; echo 'test:' ; print_list lst
+    list_set lst            ; echo 'test:' ; print_list lst
+    list_set                ; echo 'test:' ; print_list lst
+
+    list_map lst            ; echo 'test:' ; print_list lst
+    list_map inc            ; echo 'test:' ; print_list lst
+    list_map                ; echo 'test:' ; print_list lst
+
+    list_remove lst         ; echo 'test:' ; print_list lst
+    list_remove '1'         ; echo 'test:' ; print_list lst
+    list_remove             ; echo 'test:' ; print_list lst
+
+    list_erase lst          ; echo 'test:' ; print_list lst
+    list_erase '33'         ; echo 'test:' ; print_list lst
+    list_erase              ; echo 'test:' ; print_list lst
+
+    list_eraseat lst        ; echo 'test:' ; print_list lst
+    list_eraseat 3          ; echo 'test:' ; print_list lst
+    list_eraseat            ; echo 'test:' ; print_list lst
+
+    list_pop_front          ; echo 'test:' ; print_list lst
+    list_pop_back           ; echo 'test:' ; print_list lst
+
+    list_erase_from lst     ; echo 'test:' ; print_list lst
+    list_erase_from 8       ; echo 'test:' ; print_list lst
+    list_erase_from         ; echo 'test:' ; print_list lst
+
+    list_erase_range lst 0  ; echo 'test:' ; print_list lst
+    list_erase_range lst    ; echo 'test:' ; print_list lst
+    list_erase_range        ; echo 'test:' ; print_list lst
+
+    list_extract 0 1        ; echo 'test:' ; print_list lst
+    list_extract lst 1      ; echo 'test:' ; print_list lst
+    list_extract lst        ; echo 'test:' ; print_list lst
+    list_extract            ; echo 'test:' ; print_list lst
+
+    printf 'test: elt='     ; list_front    || echo
+    printf 'test: elt='     ; list_back     || echo
+
+    printf 'test: elt='     ; list_get lst  || echo
+    printf 'test: elt='     ; list_get 2    || echo
+    printf 'test: elt='     ; list_get      || echo
+
+    printf 'test: index='   ; list_indexof lst      | grep -E '^[0-9]+$' || echo
+    printf 'test: index='   ; list_indexof '-456'   | grep -E '^[0-9]+$' || echo
+    printf 'test: index='   ; list_indexof          | grep -E '^[0-9]+$' || echo
+
+    printf 'test: contains='; list_contains lst && echo 'yes' || echo 'no'
+    printf 'test: contains='; list_contains '2' && echo 'yes' || echo 'no'
+    printf 'test: contains='; list_contains     && echo 'yes' || echo 'no'
+
+    printf 'test: count='   ; list_count lst
+    printf 'test: count='   ; list_count '215'
+    printf 'test: count='   ; list_count
+
+    printf 'test: empty='   ; list_empty && echo 'yes' || echo 'no'
+}
+
+Test_VoidBadArg() {
+    Test_BadArg "$(list '' '' '' '')"
+}
+
+Test_WithBadArg() {
+    Test_BadArg "$(list 1 2 3)"
+}
diff --git a/mons b/mons
new file mode 100644
index 0000000..a509c7d
--- /dev/null
+++ b/mons
@@ -0,0 +1,448 @@
+#!/bin/sh
+#
+# The MIT License (MIT)
+#
+# Copyright (c) 2017-2018 Thomas "Ventto" Venriès <thomas.venries@gmail.com>
+#
+# Permission is hereby granted, free of charge, to any person obtaining a copy of
+# this software and associated documentation files (the "Software"), to deal in
+# the Software without restriction, including without limitation the rights to
+# use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+# the Software, and to permit persons to whom the Software is furnished to do so,
+# subject to the following conditions:
+#
+# The above copyright notice and this permission notice shall be included in all
+# copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+# FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+# COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
+# IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+# CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+usage() {
+    echo 'Usage: mons [OPTION]...
+
+Without argument, it prints connected monitors list with their names and ids.
+Options are exclusive and can be used in conjunction with extra options.
+
+Information:
+  -h    Prints this help and exits.
+  -v    Prints version and exits.
+
+Two monitors:
+  -o    Primary monitor only.
+  -s    Second monitor only.
+  -d    Duplicates the primary monitor.
+  -m    Mirrors the primary monitor.
+  -e <side>
+         Extends the primary monitor to the selected side
+         [ top | left | right | bottom ].
+  -n <side>
+         This mode selects the previous ones, one after another. The argument
+         sets the side for the extend mode.
+
+More monitors:
+  -O <mon>
+        Only enables the monitor with a specified id.
+  -S <mon1>,<mon2>:<pos>
+        Only enables two monitors with specified ids. The specified position
+        places the second monitor on the right (R) or at the top (T).
+
+Extra (in-conjunction or alone):
+  --dpi <dpi>
+        Set the DPI, a strictly positive value within the range [0 ; 27432].
+  --primary <mon_name>
+        Select a connected monitor as the primary output. Run the script
+        without argument to print monitors information, the names are in the
+        second column between ids and status. The primary monitor is marked
+        by an asterisk.
+
+Daemon mode:
+  -a    Performs an automatic display if it detects only one monitor.
+'
+}
+
+version() {
+    echo 'Mons 0.8.2
+Copyright (C) 2017 Thomas "Ventto" Venries.
+
+License MIT: <https://opensource.org/licenses/MIT>.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+'
+}
+
+# Helps to generate manpage with help2man before installing the library
+[ "$1" = '-h' ] && { usage; exit; }
+[ "$1" = '-v' ] && { version; exit; }
+lib='/usr/lib/libshlist/liblist.sh'
+[ ! -r "$lib" ] && { "$lib: library not found."; exit 1; }
+. "${lib}"
+
+arg_err() {
+    usage ; exit 2
+}
+
+enable_mon() {
+    "${XRANDR}" --output "${1}" --auto --dpi "${dpi}"
+}
+
+disable_mons() {
+    for mon in $@; do "${XRANDR}" --output "${mon}" --off ; done
+}
+
+arg2xrandr() {
+    case $1 in
+        left)   echo '--left-of'    ;;
+        right)  echo '--right-of'   ;;
+        bottom) echo '--below'      ;;
+        top)    echo '--above'      ;;
+    esac
+}
+
+whichmode() {
+    if [ "$(list_size "${disp_mons}")" -eq 1 ]; then
+        if echo "${enabled_out}" | grep prima > /dev/null 2>&1; then
+            echo 'primary'
+        else
+            echo 'second'
+        fi
+    else
+        if [ "$(list_size "${plug_mons}")" -gt 2 ] ; then
+            echo 'selection'; return 0
+        fi
+
+        enabled_out="$(echo "${enabled_out}" | \
+                        sed 's/^.*\( [0-9]\+\x[0-9]\++[0-9]\++[0-9]\+\).*/\1/')"
+
+        echo "${enabled_out}" | head -n1 | sed -e 's/+/ /g' | \
+        while read -r trash x1 y1; do
+            echo "${enabled_out}" | tail -n1 | sed -e 's/x/ /' -e 's/+/ /g' | \
+            while read -r w2 h2 x2 y2; do
+                echo "${xrandr_out}" | \
+                    awk "/^$(list_get 1 "${plug_mons}")/{nr[NR+1]}; NR in nr" | \
+                    awk '{print $1;}' | sed -e 's/x/ /' | \
+                while read -r wi2 hi2; do
+                    if [ "$x1" = "$x2" ] && [ "$y1" = "$y2" ]; then
+                        if [ "$w2" != "$wi2" ] || [ "$h2" != "$hi2" ]; then
+                            echo 'mirror'
+                        else
+                            echo 'duplicate'
+                        fi
+                    else
+                        echo 'extend'
+                    fi
+                done
+            done
+        done
+    fi
+}
+
+main() {
+    aFlag=false
+    dFlag=false
+    eFlag=false
+    mFlag=false
+    nFlag=false
+    oFlag=false
+    sFlag=false
+    OFlag=false
+    SFlag=false
+    pFlag=false
+    iFlag=false
+    is_flag=false
+    # X has assumed 96 DPI and this is fine for many traditional monitors.
+    dpi=96
+    primary=
+
+    # getopts does not support long options. We convert them to short one.
+    for arg in "$@"; do
+        shift
+        case "$arg" in
+            --dpi)      set -- "$@" '-i' ;;
+            --primary)  set -- "$@" '-p' ;;
+            *)          set -- "$@" "$arg"
+        esac
+    done
+
+    while getopts 'hvamosde:n:O:S:i:p:' opt; do
+        case $opt in
+            # Long options
+            i)
+                if ! echo "${OPTARG}" | \
+                    grep -E '^[1-9][0-9]*$' > /dev/null 2>&1; then
+                    arg_err
+                fi
+                iFlag=true; dpi="$OPTARG"
+                ;;
+            p)  if ! echo "${OPTARG}" | \
+                    grep -E '^[a-zA-Z][a-zA-Z0-9\-]+' > /dev/null 2>&1; then
+                    arg_err
+                fi
+                pFlag=true; primary="$OPTARG"
+                ;;
+            # Short options
+            a)  $is_flag && arg_err
+                aFlag=true ; is_flag=true
+                ;;
+            m)  $is_flag && arg_err
+                mFlag=true ; is_flag=true
+                ;;
+            o)  $is_flag && arg_err
+                oFlag=true ; is_flag=true
+                ;;
+            s)  $is_flag && arg_err
+                sFlag=true ; is_flag=true
+                ;;
+            d)  $is_flag && arg_err
+                dFlag=true ; is_flag=true
+                ;;
+            e|n)  $is_flag && arg_err
+                case ${OPTARG} in
+                    left | right | bottom | top) ;;
+                    *) arg_err ;;
+                esac
+                eArg=$OPTARG
+                [ "$opt" = "e" ] && eFlag=true || nFlag=true ; is_flag=true
+                ;;
+            O)  $is_flag && arg_err
+                ! echo "${OPTARG}" | grep -E '^[0-9]+$' > /dev/null && arg_err
+                OArg=$OPTARG
+                OFlag=true ; is_flag=true
+                ;;
+            S)  $is_flag && arg_err
+                idx1="$(echo "${OPTARG}" | cut -d',' -f1)"
+                idx2="$(echo "${OPTARG}" | cut -d',' -f2)"
+                area="$(echo "${idx2}" | cut -d ':' -f2)"
+                idx2="$(echo "${idx2}" | cut -d ':' -f1)"
+                ! echo "${idx1}" | grep -E '^[0-9]+$' > /dev/null && arg_err
+                ! echo "${idx2}" | grep -E '^[0-9]+$' > /dev/null && arg_err
+                ! echo "${area}" | grep -E '^[RT]$' > /dev/null && arg_err
+                [ "${idx1}" = "${idx2}" ] && arg_err
+                SFlag=true ; is_flag=true
+                ;;
+            h)  usage   ; exit ;;
+            v)  version ; exit ;;
+            \?) arg_err ;;
+            :)  arg_err ;;
+        esac
+    done
+
+    [ -z "${DISPLAY}" ] && { echo 'DISPLAY: no variable set.'; exit 1; }
+
+    XRANDR="$(command -v xrandr)"
+    [ "$?" -ne 0 ] && { echo 'xrandr: command not found.'; exit 1; }
+
+    # DPI set
+    $iFlag && [ "$#" -eq 2 ] && { "${XRANDR}" --dpi "$dpi"; exit; }
+
+    # Daemon mode
+    if $aFlag ; then
+        prev=0; i=0
+        while true; do
+            for status in /sys/class/drm/*/status; do
+                [ "$(<"$status")" = 'connected' ] && i=$((i+1))
+            done
+            if [ "$i" -eq 1 ] && [ "$i" != "$prev" ]; then
+                "${XRANDR}" --auto --dpi "${dpi}"
+            fi
+            prev="$i"; i=0
+            sleep 2
+        done
+    fi
+
+    # List all outputs (except primary one)
+    xrandr_out="$("${XRANDR}")"
+    enabled_out="$(echo "${xrandr_out}" | grep 'connect')"
+    [ -z "${enabled_out}" ] && { echo 'No monitor output detected.'; exit; }
+    mons="$(echo "${enabled_out}" | cut -d' ' -f1)"
+
+    # List plugged-in and turned-on outputs
+    enabled_out="$(echo "${enabled_out}" | grep ' connect')"
+    [ -z "${enabled_out}" ] && { echo 'No plugged-in monitor detected.'; exit 1; }
+    plug_mons="$(echo "${enabled_out}" | cut -d' ' -f1)"
+
+    if [ "$(list_size "${plug_mons}")" -eq 0 ]; then
+        echo "No monitor plugged-in."
+        exit 0
+    fi
+
+    # Set primary output
+    if $pFlag; then
+        if ! list_contains "${primary}" "${plug_mons}"; then
+            echo "${primary}: output not connected."
+            exit 1
+        fi
+        "${XRANDR}" --output "${primary}" --primary
+        [ "$#" -eq 2 ] && exit
+    else
+        primary="$(echo "${enabled_out}" | grep 'primary' | cut -d' ' -f1)"
+    fi
+
+    # Move the primary monitor to the head if connected otherwise the first
+    # connected monitor that appears in the xrandr output is considerate as
+    # the primary one.
+    if [ -n "${primary}" ]; then
+        plug_mons="$(list_erase "${primary}" "${plug_mons}")"
+        plug_mons="$(list_insert "${primary}" 0 "${plug_mons}")"
+    fi
+
+    enabled_out="$(echo "${enabled_out}" | grep -E '\+[0-9]{1,4}\+[0-9]{1,4}')"
+    disp_mons="$(echo "${enabled_out}" | cut -d' ' -f1)"
+
+    if [ "$#" -eq 0 ]; then
+        echo "Monitors: $(list_size "${plug_mons}")"
+        echo "Mode: $(whichmode)"
+
+        i=0
+        for mon in ${mons}; do
+            if echo "${plug_mons}" | grep "^${mon}$" > /dev/null; then
+                if echo "${disp_mons}" | grep "^${mon}$" > /dev/null; then
+                    state='(enabled)'
+                fi
+                if [ "${mon}" = "${primary}" ]; then
+                    printf '%-4s %-8s %-8s %-8s\n' "${i}:*" "${mon}" "${state}"
+                else
+                    printf '%-4s %-8s %-8s\n' "${i}:" "${mon}" "${state}"
+                fi
+            fi
+            i=$((i+1))
+            state=
+        done
+        exit
+    fi
+
+    if $nFlag ; then
+        case "$(whichmode)" in
+            primary)   sFlag=true;;
+            second)    eFlag=true;;
+            extend)    mFlag=true;;
+            mirror)    dFlag=true;;
+            duplicate) oFlag=true;;
+        esac
+    fi
+
+    if [ "$(list_size "${plug_mons}")" -eq 1 ] ; then
+        if $oFlag ; then
+            # After unplugging each monitor, the last preferred one might be
+            # still turned off or the window manager might need the monitor
+            # reset to cause the reconfiguration of the layout placement.
+            "${XRANDR}" --auto --dpi "${dpi}"
+        else
+            echo 'Only one monitor detected.'
+        fi
+        exit
+    fi
+
+    if $oFlag ; then
+        if [ "$(list_size "${disp_mons}")" -eq 1 ]; then
+            if [ "$(list_front "${disp_mons}")" = "$(list_front "${plug_mons}")" ]; then
+                exit
+            fi
+        fi
+        disp_mons="$(list_erase "$(list_front "${plug_mons}")" "$disp_mons")"
+        disable_mons "${disp_mons}"
+        enable_mon "$(list_front "${plug_mons}")"
+        exit
+    fi
+
+    if $OFlag ; then
+        if [ "${OArg}" -ge "$(list_size "${mons}")" ] ; then
+            echo "Monitor ID '${OArg}' does not exist."
+            echo 'Try without option to get monitor ID list.'
+            exit 2
+        fi
+        mons_elt="$(list_get "${OArg}" "${mons}")"
+        if ! list_contains "${mons_elt}" "${plug_mons}"; then
+            echo "Monitor ID '${OArg}' not plugged in."
+            echo 'Try without option to get monitor ID list.'
+            exit 2
+        fi
+
+        disp_mons="$(list_erase "${mons_elt}" "${disp_mons}")"
+        disable_mons "${disp_mons}"
+        enable_mon "${mons_elt}"
+        exit
+    fi
+
+    if $SFlag ; then
+        if [ "${idx1}" -ge "$(list_size "${mons}")" ] || \
+            [ "${idx2}" -ge "$(list_size "${mons}")" ]; then
+            echo 'One or both monitor IDs do not exist.'
+            echo 'Try without option to get monitor ID list.'
+            exit 2
+        fi
+        if ! list_contains "$(list_get "${idx1}" "${mons}")" "${plug_mons}" || \
+            ! list_contains "$(list_get "${idx2}" "${mons}")" "${plug_mons}" ; then
+            echo 'One or both monitor IDs are not plugged in.'
+            echo 'Try without option to get monitor ID list.'
+            exit 2
+        fi
+
+        [ "${area}" = 'R' ] && area="--right-of" || area="--above"
+
+        mon1="$(list_get "${idx1}" "${mons}")"
+        mon2="$(list_get "${idx2}" "${mons}")"
+        disp_mons="$(list_erase "${mon1}" "${disp_mons}")"
+        disp_mons="$(list_erase "${mon2}" "${disp_mons}")"
+        disable_mons "${disp_mons}"
+        enable_mon "${mon1}"
+        enable_mon "${mon2}"
+        "${XRANDR}" --output "${mon2}" "${area}" "${mon1}"
+        exit
+    fi
+
+    if [ "$(list_size "${plug_mons}")" -eq 2 ]; then
+        if $sFlag ; then
+            if [ "$(list_size "${disp_mons}")" -eq 1 ] ; then
+                if [ "$(list_front "${disp_mons}")" = "$(list_get 1 "${plug_mons}")" ] ; then
+                    enable_mon "$(list_get 1 "${plug_mons}")"
+                    exit
+                fi
+            fi
+            enable_mon "$(list_get 1 "${plug_mons}")"
+            disable_mons "$(list_front "${disp_mons}")"
+            exit
+        fi
+
+        # Resets the screen configuration
+        disable_mons "$(list_get 1 "${plug_mons}")"
+        "${XRANDR}" --auto --dpi "${dpi}"
+
+        if $dFlag ; then
+            "${XRANDR}" --output "$(list_get 1 "${plug_mons}")" \
+                --same-as "$(list_front "${plug_mons}")"
+            exit $?
+        fi
+
+        if $mFlag ; then
+            xrandr_out="$(echo "${xrandr_out}" | \
+                          awk "/primary/{nr[NR]; nr[NR+1]}; NR in nr")"
+            if echo "${xrandr_out}" | \
+                grep -E 'primary [0-9]+x[0-9]+' >/dev/null 2>&1; then
+                size="$(echo "${xrandr_out}" | head -n1 | cut -d' ' -f4 | \
+                        cut -d'+' -f1)"
+            else
+                size="$(echo "${xrandr_out}" | tail -n1 | awk '{ print $1 }')"
+            fi
+
+            "${XRANDR}" --output "$(list_get 1 "${plug_mons}")" \
+                --auto --scale-from  "${size}" \
+                --output "$(list_front "${plug_mons}")"
+            exit $?
+        fi
+
+        if $eFlag ; then
+            "${XRANDR}" --output "$(list_get 1 "${plug_mons}")" \
+                "$(arg2xrandr "$eArg")" "$(list_front "${plug_mons}")"
+            exit $?
+        fi
+    else
+        echo 'At most two plugged monitors for this option.'
+    fi
+}
+
+main "$@"
diff --git a/mons.1.gz b/mons.1.gz
new file mode 100644
index 0000000..0b5d8de
Binary files /dev/null and b/mons.1.gz differ
diff --git a/test/test-args.sh b/test/test-args.sh
new file mode 100644
index 0000000..8b37179
--- /dev/null
+++ b/test/test-args.sh
@@ -0,0 +1,77 @@
+#!/bin/sh
+
+if [ "$#" -ne 3 ]; then
+    echo 'Usage: test-args.sh MON_ID1 MON_ID2 MON_ID3'
+    echo
+    echo 'Three monitor ids are required. Ids are given by `mons`.'
+    exit 1
+fi
+
+echo 'TEST: Bad Arguments'
+echo '#=========================#'
+./mons
+echo '#=========================#'
+echo 'test: common'
+
+n=1
+./mons --s -o       >/dev/null 2>&1 && echo "failed: $n" ; n=$((n+1))
+./mons --o          >/dev/null 2>&1 && echo "failed: $n" ; n=$((n+1))
+./mons -e fekl56    >/dev/null 2>&1 && echo "failed: $n" ; n=$((n+1))
+./mons -e 2         >/dev/null 2>&1 && echo "failed: $n" ; n=$((n+1))
+./mons -e pot       >/dev/null 2>&1 && echo "failed: $n" ; n=$((n+1))
+./mons -d 2         >/dev/null 2>&1 || echo "failed: $n" ; n=$((n+1))
+./mons -m 2         >/dev/null 2>&1 || echo "failed: $n" ; n=$((n+1))
+
+echo 'test: single selection'
+
+n=1
+./mons -O 5 "$1"    >/dev/null 2>&1 && echo "failed: $n" ; n=$((n+1))
+./mons -O abc "$2"  >/dev/null 2>&1 && echo "failed: $n" ; n=$((n+1))
+./mons --O "$3"     >/dev/null 2>&1 && echo "failed: $n" ; n=$((n+1))
+./mons -O           >/dev/null 2>&1 && echo "failed: $n" ; n=$((n+1))
+
+echo 'test: multi selection'
+
+n=1
+./mons -S           >/dev/null 2>&1 && echo "failed: $n" ; n=$((n+1))
+./mons -S "$1,$2:P" >/dev/null 2>&1 && echo "failed: $n" ; n=$((n+1))
+./mons -S "$3,$2:5" >/dev/null 2>&1 && echo "failed: $n" ; n=$((n+1))
+./mons -S "$2:R"    >/dev/null 2>&1 && echo "failed: $n" ; n=$((n+1))
+./mons -S "$3,$1"   >/dev/null 2>&1 && echo "failed: $n" ; n=$((n+1))
+./mons -S "A,B:R"   >/dev/null 2>&1 && echo "failed: $n" ; n=$((n+1))
+
+echo 'test: dpi'
+
+n=1
+./mons --dpi                >/dev/null 2>&1 && echo "failed: $n" ; n=$((n+1))
+./mons --dpi A              >/dev/null 2>&1 && echo "failed: $n" ; n=$((n+1))
+./mons --dpi 0              >/dev/null 2>&1 && echo "failed: $n" ; n=$((n+1))
+./mons --dpi -0             >/dev/null 2>&1 && echo "failed: $n" ; n=$((n+1))
+./mons --dpi -5             >/dev/null 2>&1 && echo "failed: $n" ; n=$((n+1))
+./mons --dpi -3000          >/dev/null 2>&1 && echo "failed: $n" ; n=$((n+1))
+./mons --dpi -s 1           >/dev/null 2>&1 && echo "failed: $n" ; n=$((n+1))
+# Weird configuration
+./mons -e --dpi 96 left     >/dev/null 2>&1 || echo "failed: $n" ; n=$((n+1))
+./mons -n --dpi 72 right    >/dev/null 2>&1 || echo "failed: $n" ; n=$((n+1))
+
+echo 'test: primary'
+n=1
+./mons --primary                >/dev/null 2>&1 && echo "failed: $n" ; n=$((n+1))
+./mons --primary -HDMI1         >/dev/null 2>&1 && echo "failed: $n" ; n=$((n+1))
+./mons --primary -HDMI1         >/dev/null 2>&1 && echo "failed: $n" ; n=$((n+1))
+./mons --primary 1HDMI          >/dev/null 2>&1 && echo "failed: $n" ; n=$((n+1))
+./mons --primary -s 1           >/dev/null 2>&1 && echo "failed: $n" ; n=$((n+1))
+./mons -n --primary HDMI1       >/dev/null 2>&1 && echo "failed: $n" ; n=$((n+1))
+./mons -n --primary HDMI1 left  >/dev/null 2>&1 || echo "failed: $n" ; n=$((n+1))
+./mons -n --primary HDMI1 left -s   >/dev/null 2>&1 && echo "failed: $n" ; n=$((n+1))
+
+echo 'test: dpi + primary'
+n=1
+./mons --primary --dpi          >/dev/null 2>&1 && echo "failed: $n" ; n=$((n+1))
+./mons --primary --dpi 75       >/dev/null 2>&1 && echo "failed: $n" ; n=$((n+1))
+./mons --primary HDMI1 --dpi    >/dev/null 2>&1 && echo "failed: $n" ; n=$((n+1))
+./mons --primary HDMI1 --dpi 0  >/dev/null 2>&1 && echo "failed: $n" ; n=$((n+1))
+./mons --primary 1HDMI --dpi 0  >/dev/null 2>&1 && echo "failed: $n" ; n=$((n+1))
+./mons --primary HDMI1 --dpi HDMI1  >/dev/null 2>&1 && echo "failed: $n" ; n=$((n+1))
+./mons --primary HDMI1 --dpi 75 >/dev/null 2>&1 && echo "failed: $n" ; n=$((n+1))
+./mons -n --primary HDMI1 --dpi 75 left >/dev/null 2>&1 || echo "failed: $n" ; n=$((n+1))
diff --git a/test/test-common.sh b/test/test-common.sh
new file mode 100644
index 0000000..d5db31d
--- /dev/null
+++ b/test/test-common.sh
@@ -0,0 +1,36 @@
+#!/bin/sh
+
+if [ "$#" -ne 2 ]; then
+    echo 'Usage: test-common.sh CURR_MON_NAME MON_NAME'
+    echo
+    echo 'Monitor names are required. Names are given by "mons".
+CURR_MON_NAME is your current monitor and the second one is reserved
+for primary test.'
+    exit 1
+fi
+
+Test_Common () {
+    echo 'TEST: Common Modes'
+    echo '#=========================#'
+    ./mons
+    echo '#=========================#'
+
+    ./mons -o           ; echo "test: primary"          ; sleep 8
+    ./mons -s           ; echo "test: second"           ; sleep 8
+    ./mons -e left      ; echo "test: extend left"      ; sleep 8
+    ./mons -d           ; echo "test: duplicate"        ; sleep 8
+    ./mons -m           ; echo "test: mirror"           ; sleep 8
+    ./mons -e right     ; echo "test: extend right"     ; sleep 8
+    ./mons -e top       ; echo "test: extend top"       ; sleep 8
+    ./mons -e bottom    ; echo "test: extend bottom"    ; sleep 8
+    ./mons -o           ; echo "test: primary"          ; sleep 8
+    ./mons -s           ; echo "test: second"           ; sleep 8
+    ./mons -o           ; echo "test: primary"
+}
+
+./mons -o --primary "$1"
+Test_Common
+./mons -o --primary "$2"
+echo "[ Primary has been set: $1 ]"
+Test_Common
+./mons -o --primary "$1"
diff --git a/test/test-select.sh b/test/test-select.sh
new file mode 100644
index 0000000..151c79f
--- /dev/null
+++ b/test/test-select.sh
@@ -0,0 +1,24 @@
+#!/bin/sh
+
+if [ "$#" -ne 3 ]; then
+    echo 'Usage: test-select.sh MON_ID1 MON_ID2 MON_ID3'
+    echo
+    echo 'Three monitor ids are required. Ids are given by `mons`.'
+    exit 1
+fi
+
+echo 'TEST: Selections'
+echo '#=========================#'
+./mons
+echo '#=========================#'
+
+./mons -O "$1"      ; echo "test: single select $1"         ; sleep 8
+./mons -O "$2"      ; echo "test: single select $2"         ; sleep 8
+./mons -O "$3"      ; echo "test: single select $3"         ; sleep 8
+./mons -O "$1"      ; echo "test: single select $1"         ; sleep 8
+./mons -S "$1,$2:R" ; echo "test: single select $1,$2:R"    ; sleep 8
+./mons -S "$1,$2:T" ; echo "test: multi select $1,$2:T"     ; sleep 8
+./mons -S "$3,$2:T" ; echo "test: multi select $3,$2:T"     ; sleep 8
+./mons -S "$2,$3:R" ; echo "test: multi select $2,$3:R"     ; sleep 8
+./mons -S "$3,$1:T" ; echo "test: multi select $3,$1:T"     ; sleep 8
+./mons -O "$1"      ; echo "test: single select $1"