Bash Shell Scripting/External Programs

Bash, as a shell, is actually a 'glue' language. It helps programs to cooperate with each other, and benefits from it. Always Search The Internet for what you want -- there are lots of command line utilities available.

Using whiptail
Whiptail is a program that allows shell scripts to display dialog boxes to the user for informational purposes, or to get input from the user in a friendly way. Whiptail is included by default on Debian and various other GNU/Linux distributions.
 * From the GNU/Linux Dictionary: whiptail is a "dialog" replacement using newt instead of ncurses.
 * From its README: whiptail is designed to be drop-in compatible with dialog(1), but has fewer features: some dialog boxes are not implemented, such as tailbox, timebox, calendarbox, etc.

See Bash Shell Scripting/Whiptail.

Using AWK
See AWK and.

Using sed
See sed and.

Using grep
See grep and.

Using man, info and help
These three programs are where you can find help or reference from. displays roff manual pages,  displays texinfo documentations, while   displays builtin helps.

Appending,   or   to a command-line program may also gives you the usage information. Possible synonyms include  and.

Just try these out: Pressing  in   and  's interfaces can also give you some direction.