4.1. Overview of Features

The Bash and Korn shells provide the following features:

• Input/output redirection

• Wildcard characters (metacharacters) for filename abbreviation

• Shell variables and options for customizing your environment

• A built-in command set for writing shell programs

• Shell functions, for modularizing tasks within a shell program

• Job control

• Command-line editing (using the command syntax of either vi or Emacs)

• Access to previous commands (command history)

• Integer arithmetic

• Arrays and arithmetic expressions

• Command-name abbreviation (aliasing)

ksh93 and Bash (but not ksh88) have the following capabilities:

• Upwards compliance with POSIX

• Internationalization facilities

• An arithmetic for loop

• More ways to substitute variables

ksh93 adds the following capabilities:

• Floating-point arithmetic and built-in arithmetic functions

• Structured variable names and indirect variable references

• Associative arrays

• More ways to match patterns