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- PS1 The value of this parameter is expanded (see PROMPTING below) and used as the primary
- prompt string. The default value is ``\s-\v\$ ''.
- PS2 The value of this parameter is expanded as with PS1 and used as the secondary prompt
- string. The default is ``> ''.
- PS3 The value of this parameter is used as the prompt for the select command (see SHELL
- GRAMMAR above).
- PS4 The value of this parameter is expanded as with PS1 and the value is printed before
- each command bash displays during an execution trace. The first character of PS4 is
- replicated multiple times, as necessary, to indicate multiple levels of indirection.
- The default is ``+ ''.
- PROMPTING
- When executing interactively, bash displays the primary prompt PS1 when it is ready to read a
- command, and the secondary prompt PS2 when it needs more input to complete a command. Bash
- allows these prompt strings to be customized by inserting a number of backslash-escaped spe-
- cial characters that are decoded as follows:
- \a an ASCII bell character (07)
- \d the date in "Weekday Month Date" format (e.g., "Tue May 26")
- \D{format}
- the format is passed to strftime(3) and the result is inserted into the prompt
- string; an empty format results in a locale-specific time representation. The
- braces are required
- \e an ASCII escape character (033)
- \h the hostname up to the first `.'
- \H the hostname
- \j the number of jobs currently managed by the shell
- \l the basename of the shell's terminal device name
- \n newline
- \r carriage return
- \s the name of the shell, the basename of $0 (the portion following the final
- slash)
- \t the current time in 24-hour HH:MM:SS format
- \T the current time in 12-hour HH:MM:SS format
- \@ the current time in 12-hour am/pm format
- \A the current time in 24-hour HH:MM format
- \u the username of the current user
- \v the version of bash (e.g., 2.00)
- \V the release of bash, version + patch level (e.g., 2.00.0)
- \w the current working directory, with $HOME abbreviated with a tilde
- \W the basename of the current working directory, with $HOME abbreviated with a
- tilde
- \! the history number of this command
- \# the command number of this command
- \$ if the effective UID is 0, a #, otherwise a $
- \nnn the character corresponding to the octal number nnn
- \\ a backslash
- \[ begin a sequence of non-printing characters, which could be used to embed a ter-
- minal control sequence into the prompt
- \] end a sequence of non-printing characters
- The command number and the history number are usually different: the history number of a com-
- mand is its position in the history list, which may include commands restored from the history
- file (see HISTORY below), while the command number is the position in the sequence of commands
- executed during the current shell session. After the string is decoded, it is expanded via
- parameter expansion, command substitution, arithmetic expansion, and quote removal, subject to
- the value of the promptvars shell option (see the description of the shopt command under SHELL
- BUILTIN COMMANDS below).