BASH
Probably the most popular command line shell with Linux distributions. The name came from a pun on Stephen Bourne, the author's name as Bourne Again SHell.
Bash is a shell, or command language interpreter. Bash is an sh-compatible* shell that incorporates useful features from the Korn shell (ksh) and C shell (csh). It offers functional improvements over sh for both programming and interactive use. In addition, most sh scripts can be run by Bash without modification.
Scripts
A script is a text file with shell commands. The script needs to have the execute flag set before executing.
It can be set by chmod +x filename the filename is the name of the script file.
Below is a sample script for the iconic "Hello World" example that can be created with a simple text editor. The script file's executable flag must be set before running it.
#/bin/bash
# Hello World bash script
echo Hello World
When the above file (I named it helloworld) is ran you should see something like the following.
~$ ./helloworld
Hello World
Bash scripts can be a very powerful way to run all sorts of tasks.
Notice the pound sign # (Hashtag to the youngsters) means the line is a comment.
Links
Linux Command.org LinuxCommand.org is a web site devoted to helping users of legacy operating systems discover the power of Linux. It is a good place to start learning more about Bash.
Zenity is free software that adds popup graphical interfaces and dialogs to a script.
Documentation
BASH Manuals Download Free Manuals as:
HTML One Page (gzipped)
HTML Multiple pages (gzipped tar ball)
BASH Guide For Beginners (PDF download)
Advanced Bash-Scripting Guide (PDF download)
Example Scripts
Notes
* sh - shell, the standard command language interpreter that BASH is a improvement on. In most cases SH has been pretty much been replaced by BASH as the default shell. Read More on sh at: The Open Group Base Publications