Bash and Korn Shell Environment Variables

The bash and ksh93 shells store special variable information that is known to the shell as an environment variable. To view a complete list of the current environment variables for the bash shell, use the declare command.

$ declare
BASH=/usr/bin/bash
BASH_ARGC=()
BASH_ARGV=()
BASH_LINEND=()
BASH_SOuRCE=()
BASH_VERSINFO=([0]=''3'' [1]=''2'' [2]=''25'' [3]=''1''
[4]=''release'' [5]''
.
.
.

For the ksh93 shell, use the set command, which is the bash shell's declare command equivalent.

$ set
  COLUMNS=80
  ENV='$HOME/.kshrc'
  FCEDIT=/bin/ed
  HISTCMD=3
  HZ=''
  IFS=$' \t\n'
  KSH_VERSION=.sh.version
  LANG=C
  LINENO=1
  .
  .
  .

To print environment variables for either shell, use the echo or printf command. For example:

$ echo $SHELL
/usr/bin/bash
$ printf "$PATH\n"
/usr/bin:/usr/sbin

A shell can have two types of variables:

Environment variables

Specifies variables that are exported to all processes that are spawned by the shell. The export command is used to export a variable. For example:

export VARIABLE=value

These settings can be displayed by using the env command. A subset of environment variables, such as PATH, affects the behavior of the shell itself.

Shell (local) variables

Specifies variables that affect only the current shell.

In a user initialization file, you can customize a user's shell environment by changing the values of the predefined variables or by specifying additional variables.

The following table provides more details about the shell and environment variables that are available in the Oracle Solaris release.