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+*Jump to [source](pacman.rs)*
+
+[`pacman`](https://wiki.archlinux.org/index.php/pacman) defines subcommands via flags.
+
+Here, `-S` is a short flag subcommand:
+```console
+$ pacman -S package
+Installing package...
+
+```
+
+Here `--sync` is a long flag subcommand:
+```console
+$ pacman --sync package
+Installing package...
+
+```
+
+Now the short flag subcommand (`-S`) with a long flag:
+```console
+$ pacman -S --search name
+Searching for name...
+
+```
+
+And the various forms of short flags that work:
+```console
+$ pacman -S -s name
+Searching for name...
+
+$ pacman -Ss name
+Searching for name...
+
+```
+*(users can "stack" short subcommands with short flags or with other short flag subcommands)*
+
+In the help, this looks like:
+```console
+$ pacman -h
+pacman 5.2.1
+Pacman Development Team
+package manager utility
+
+USAGE:
+    pacman[EXE] <SUBCOMMAND>
+
+OPTIONS:
+    -h, --help       Print help information
+    -V, --version    Print version information
+
+SUBCOMMANDS:
+    help                Print this message or the help of the given subcommand(s)
+    query -Q --query    Query the package database.
+    sync -S --sync      Synchronize packages.
+
+$ pacman -S -h
+pacman[EXE]-sync 
+Synchronize packages.
+
+USAGE:
+    pacman[EXE] {sync|--sync|-S} [OPTIONS] [--] [package]...
+
+ARGS:
+    <package>...    packages
+
+OPTIONS:
+    -h, --help                  Print help information
+    -i, --info                  view package information
+    -s, --search <search>...    search remote repositories for matching strings
+
+```
+
+And errors:
+```console
+$ pacman -S -s foo -i bar
+? failed
+error: The argument '--search <search>...' cannot be used with '--info'
+
+USAGE:
+    pacman[EXE] {sync|--sync|-S} --search <search>... <package>...
+
+For more information try --help
+
+```
+
+**NOTE:** Keep in mind that subcommands, flags, and long flags are *case sensitive*: `-Q` and `-q` are different flags/subcommands. For example, you can have both `-Q` subcommand and `-q` flag, and they will be properly disambiguated.
+Let's make a quick program to illustrate.