z/OS V1R9.0 UNIX System Services Command ... - Christian Grothoff

sh
Table 28. Built-in Shell Variables (sh command) (continued)
Variable Purpose
MAILPATH Contains a list of mailbox files. This overrides the MAIL variable.
The mailbox list is separated by colons. If any name is followed by
?message or %message, sh displays the message if the
corresponding file has changed. sh performs parameter and
command substitution on message, and the variable _. (temporarily)
expands to the name of the mailbox file. If no ?message or %
message is present, the default message is you have mail in $_.
MANPATH Contains a list of paths to search for man pages.
MBOX Contains the pathname of your personal mailbox, usually
$HOME/mbox, used to store messages that have been read from
your system mailbox. This variable is usually set in your .profile.
NLSPATH Specifies where the message catalogs are to be found.
OLDPWD Contains the name of the directory you were previously working in.
The cd command sets this variable.
PATH Contains a list of directories that the system searches to find
executable commands. Directories in this list are separated with
colons. sh searches each directory in the order specified in the list
until it finds a matching executable. If you want the shell to search
the working directory, put a dot (.) or a null string in the list of
directories (for example, to tell the shell to search the working
directory first, start the list with a colon or semicolon).
PPID Contains the decimal value of the process ID of the parent of the
shell. If running in a child shell environment (see “Shell Execution
Environments” on page 567), the PPID value is the same as the
PPID value of the current shell.
PS1 Contains the primary prompt string used when the shell is
interactive.The default value is a dollar sign followed by a space
($ ). The shell expands parameters before the prompt is printed. A
single exclamation mark (!) in the prompt string is replaced by the
command number from the history list; see the fc command. For a
real exclamation mark in the prompt, use !!. This variable is usually
set in your .profile.
PS2 Contains the secondary prompt, or continuation prompt, used when
completing the input of such things as reserved-word commands,
quoted strings, and here documents. The default value of this
variable is a greater than sign followed by a space (> ).
PS3 Contains the prompt string used in connection with the select
reserved word. The default value is a number sign followed by a
question mark and a space (#? ).
PS4 Contains the prefix for traced commands with set -x. The default
value is a plus sign followed by a space (+ ).
PWD Contains the name of the working directory. When the shell starts,
the working directory name is assigned to PWD unless the variable
already has a value.
RANDOM Returns a random integer. Setting this variable sets a new seed for
the random number generator.
SECONDS Contains elapsed time. The value of this variable grows by 1 for
each elapsed second of real time. Any value assigned to this
variable sets the SECONDS counter to that value; initially the shell
sets the value to 0.
572 z/OS V1R9.0 UNIX System Services Command Reference