[`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
package manager utility
Usage: pacman[EXE] <COMMAND>
Commands:
query, -Q, --query Query the package database.
sync, -S, --sync Synchronize packages.
help Print this message or the help of the given subcommand(s)
Options:
-h, --help Print help information
-V, --version Print version information
$ pacman -S -h
Synchronize packages.
Arguments:
[package]... packages
Options:
-s, --search <search>... search remote repositories for matching strings
-i, --info view package information
-h, --help Print help information
```
And errors:
```console
$ pacman -S -s foo -i bar
? failed
error: The argument '--search <search>...' cannot be used with '--info'
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.