Other Shell Variables

HOME=directory
The home directory is set by the login from the /etc/passwd file.
IFS='chars'
IFS are the input field separators. The default value of the string is space, tab and newline.
OPTERR=n
If n=1, which is the default value, then Bash prints error messages from the built-in getopts command.
PATH=pathname_list
One or more pathnames, delimited by colons, in which to search for commands to execute. /bin:/usr/bin is the default on some systems.
PS1=string
The primary prompt string. The default value is $. See also: example in the Special Prompt Strings page.
PS2=string
The secondary prompt string is used in multiline commands. The default value is >.
PS3=string
The prompt string used in select loops. The default value is #?. See also: The SELECT statement.
PS4=string
The prompt string for execution trace: bash -x or set -x. The default value is +.
SHELL=path_to_binary
The path to user’s default shell, which is often /bin/sh. If this variable is not in the environment at startup, then Bash sets it.

2020–07–16