Add shell completions and manpage

* Add manpage

Adds a basic manpage that was autogenerated with `help2man` and then
slightly adjusted with information from the README.md and better
formatting.

* Add zsh completions

Add completions for the zsh shell. These should be complete and even
allow completion of the command inside `--command` and `-e`.

* Add bash completions

The bash completions are almost on the same level as the zsh
completions. The only little thing the bash completions do not do is
complete inside of `--command` and `-e`, instead bash just stops
completion after these options.

* Update readme with manpage and completions

Added the install instructions for the manpage and completions to the
README.md.

Also tweaked the current readme a slight bit because the build section
was structured in a slightly confusing way.

4 files changed, 199 insertions, 3 deletions

diff --git a/README.md b/README.md
index 89b324b9..f2237098 100644
--- a/README.md
+++ b/README.md
@@ -213,6 +213,11 @@ filling in this section of the README.
 
 ### Building
 
+**BEFORE YOU RUN IT:** Install the config file as described below; otherwise,
+many things (such as arrow keys) will not work.
+
+#### Linux
+
 Once all the prerequisites are installed, compiling Alacritty should be easy:
 
 ```sh
@@ -220,10 +225,8 @@ cargo build --release
 ```
 
 If all goes well, this should place a binary at `target/release/alacritty`.
-**BEFORE YOU RUN IT:** Install the config file as described below; otherwise,
-many things (such as arrow keys) will not work.
 
-### Desktop Entry
+##### Desktop Entry
 
 Many linux distributions support desktop entries for adding applications to
 system menus. To install the desktop entry for Alacritty, run
@@ -233,6 +236,8 @@ sudo cp target/release/alacritty /usr/local/bin # or anywhere else in $PATH
 cp Alacritty.desktop ~/.local/share/applications
 ```
 
+#### MacOS
+
 To build an application for macOS, run
 
 ```sh
@@ -240,6 +245,46 @@ make app
 cp -r target/release/osx/Alacritty.app /Applications/
 ```
 
+## Manual Page
+
+Installing the manual page requires the additional dependency `gzip`.
+To install the manual page, run
+
+```sh
+sudo mkdir -p /usr/local/share/man/man1
+gzip -c alacritty.man | sudo tee /usr/local/share/man/man1/alacritty.1.gz > /dev/null
+```
+
+## Shell completions
+
+To get automatic completions for alacritty's flags and arguments you can install the provided shell completions.
+
+### Zsh
+
+To install the completions for zsh, run
+
+```
+sudo cp alacritty-completions.zsh /usr/share/zsh/functions/Completion/X/_alacritty
+```
+
+### Bash
+
+To install the completions for bash, you can `source` the `alacritty-completions.bash` in your `~/.bashrc` file.
+
+If you do not plan to delete the source folder of alacritty, you can run
+
+```sh
+echo "source $(pwd)/alacritty-completions.bash" >> ~/.bashrc
+```
+
+Otherwise you can copy it to the `~/.bash_completion` folder and source it from there:
+
+```sh
+mkdir -p ~/.bash_completion
+cp alacritty-completions.bash ~/.bash_completion/alacritty
+echo "source ~/.bash_completion/alacritty" >> ~/.bashrc
+```
+
 ## Configuration
 
 Although it's possible the default configuration would work on your system,
diff --git a/alacritty-completions.bash b/alacritty-completions.bash
new file mode 100644
index 00000000..57191515
--- /dev/null
+++ b/alacritty-completions.bash
@@ -0,0 +1,58 @@
+#/usr/bin/env bash
+
+# Load completion function
+complete -F _alacritty alacritty
+
+# Completion function
+_alacritty()
+{
+    local cur prev prevprev opts
+    COMPREPLY=()
+    cur="${COMP_WORDS[COMP_CWORD]}"
+    prev="${COMP_WORDS[COMP_CWORD-1]}"
+    prevprev="${COMP_WORDS[COMP_CWORD-2]}"
+    opts="-h --help -V --version --live-config-reload --no-live-config-reload --print-events -q -qq -v -vv -vvv --ref-test -e --command --config-file -d --dimensions -t --title --working-directory"
+
+    # If `--command` or `-e` is used, stop completing
+    for i in "${!COMP_WORDS[@]}"; do
+        echo "${COMP_WORDS[i]}" >> ./testfile
+        if [[ "${COMP_WORDS[i]}" == "--command" ]] \
+            || [[ "${COMP_WORDS[i]}" == "-e" ]] \
+            && [[ "${#COMP_WORDS[@]}" -gt "$(($i + 2))" ]]
+        then
+            return 0
+        fi
+    done
+
+    # Make sure the Y dimension isn't completed
+    if [[ "${prevprev}" == "--dimensions" ]] || [[ "${prevprev}" == "-d" ]]; then
+        return 0
+    fi
+
+    # Match the previous word
+    case "${prev}" in
+        --command | -e)
+            # Complete all commands in $PATH
+            COMPREPLY=( $(compgen -c -- "${cur}") )
+            return 0;;
+        --config-file)
+            # Path based completion
+            local IFS=$'\n'
+            compopt -o filenames
+            COMPREPLY=( $(compgen -f -- "${cur}") )
+            return 0;;
+        --dimensions | -d | --title | -t)
+            # Don't complete here
+            return 0;;
+        --working-directory)
+            # Directory completion
+            local IFS=$'\n'
+            compopt -o filenames
+            COMPREPLY=( $(compgen -d -- "${cur}") )
+            return 0;;
+    esac
+
+    # Show all flags if there was no previous word
+    COMPREPLY=( $(compgen -W "${opts}" -- "${cur}") )
+    return 0
+}
diff --git a/alacritty-completions.zsh b/alacritty-completions.zsh
new file mode 100644
index 00000000..d2cc0eea
--- /dev/null
+++ b/alacritty-completions.zsh
@@ -0,0 +1,23 @@
+#compdef alacritty
+
+_alacritty() {
+    local context curcontext="$curcontext" state line
+    typeset -A opt_args
+
+    _arguments \
+        "(-h --help)"{-h,--help}"[Prints help information]" \
+        "(-V --version)"{-V,--version}"[Prints version information]" \
+        "(--no-live-config-reload)--live-config-reload[Enable automatic config reloading]" \
+        "(--live-config-reload)--no-live-config-reload[Disable automatic config reloading]" \
+        "--print-events[Print all events to stdout]" \
+        {-q,-qq}"[Reduces the level of verbosity (min is -qq)]" \
+        {-v,-vv,-vvv}"[Increases the level of verbosity (max is -vvv)]" \
+        "--ref-test[Generates ref test]" \
+        "--config-file[Specify an alternative config file]:file:_files" \
+        "(-d --dimensions)"{-d,--dimensions}"[Window dimensions]:dimensions:_guard '<->' width: :_guard '<->' length" \
+        "--title[Defines the window title]:title:" \
+        "--working-directory[Start shell in specified directory]:directory:_dir_list" \
+        "(-e --command)"{-e,--command}"[Execute command (must be last arg)]:program: _command_names -e:*::program arguments: _normal"
+}
+
+_alacritty "$@"
diff --git a/alacritty.man b/alacritty.man
new file mode 100644
index 00000000..31e2934e
--- /dev/null
+++ b/alacritty.man
@@ -0,0 +1,70 @@
+.\" DO NOT MODIFY THIS FILE!  It was generated by help2man 1.47.5.
+.TH ALACRITTY "1" "March 2018" "alacritty 0.1.0" "User Commands"
+.SH NAME
+alacritty \- a cross-platform, gpu-accelerated terminal emulator
+.SH "SYNOPSIS"
+alacritty [FLAGS] [OPTIONS]
+.SH DESCRIPTION
+Alacritty is focused on simplicity and performance.
+.TP
+The performance goal means it should be faster than any other terminal emulator available.
+.TP
+The simplicity goal means that it doesn't have features such as tabs or splits (which can be better provided by a window manager or terminal multiplexer) nor niceties like a GUI config editor.
+.SH "FLAGS"
+.TP
+\fB\-h\fR, \fB\-\-help\fR
+Prints help information
+.TP
+\fB\-\-live\-config\-reload\fR
+Enable automatic config reloading
+.TP
+\fB\-\-no\-live\-config\-reload\fR
+Disable automatic config reloading
+.HP
+\fB\-\-print\-events\fR
+.TP
+\fB\-q\fR
+Reduces the level of verbosity (the min level is \fB\-qq\fR)
+.TP
+\fB\-\-ref\-test\fR
+Generates ref test
+.TP
+\fB\-v\fR
+Increases the level of verbosity (the max level is \fB\-vvv\fR)
+.TP
+\fB\-V\fR, \fB\-\-version\fR
+Prints version information
+.SH "OPTIONS"
+.TP
+\fB\-e\fR, \fB\-\-command\fR <command>...
+Command and args to execute (must be last argument)
+.HP
+\fB\-\-config\-file\fR <config\-file>
+.IP
+Specify alternative configuration file [default: $XDG_CONFIG_HOME/alacritty/alacritty.yml]
+.HP
+\fB\-d\fR, \fB\-\-dimensions\fR <columns> <lines>
+.IP
+Defines the window dimensions. Falls back to size specified by window manager if set to 0x0 [default: 80x24]
+.TP
+\fB\-t\fR, \fB\-\-title\fR <title>
+Defines the window title [default: Alacritty]
+.TP
+\fB\-\-working\-directory\fR <working\-directory>
+Start the shell in the specified working directory
+.SH "SEE ALSO"
+See the alacritty github repository at https://github.com/jwilm/alacritty for the full documentation.
+.SH "BUGS"
+Found a bug? Please report it at https://github.com/jwilm/alacritty/issues.
+.SH "AUTHORS"
+Maintainers:
+.sp
+.RS 4
+.ie n \{\
+\h'-04'\(bu\h'+03'\c
+.\}
+.el \{\
+.sp -1
+.IP \(bu 2.3
+.\}
+Joe Wilm <joe@jwilm.com>