Input/output redirection
Wildcard characters (metacharacters) for filename abbreviation
Shell variables for customizing your environment
A built-in command set for writing shell programs
Job control (beginning in SVR4)
The Korn shell is a backward-compatible extension of the Bourne shell.
Features that are valid only in the Korn shell are
so indicated:
Command-line editing (using the command syntax of either
vi or emacs)
Access to previous commands (command history)
Integer arithmetic
More ways to match patterns and substitute variables
Arrays and arithmetic expressions
Command-name abbreviation (aliasing)
More built-in commands
ksh93 adds the following capabilities:
Upwards compliance with POSIX
Internationalization facilities
An arithmetic for loop
Floating-point arithmetic and built-in arithmetic functions
Structured variable names and indirect variable references
Associative arrays
Even more ways to match patterns and substitute variables
Even more built-in commands