The following commands include shells and programs useful in shell scripts.
Bourne Again shell (default).
Repeats command-line arguments on standard output.
Performs arithmetic and comparisons.
Reads a line of input.
Makes sure that a file is accessed by only one script at a time.
Practical Extraction and Report Language, Version 5.8.1 RC3.
PHP scripting language Version 4.3.2, used for web development.
Formats and prints command-line arguments.
Python scripting language, Version 2.3.
Ruby scripting language, Version 1.6.8.
Standard Unix shell.
Causes a pause during processing.
Tool Command Language (Tcl) shell, Version 8.4.
Tenex C shell.
Command that tests a condition.
Command that reads arguments from standard input and passes them to a command.
Enhanced Unix shell.