dir
Makes the current working directory be the top of the stack, mak- ing it the new current directory as if it had been supplied as an argument to the cd builtin.
6.9 Controlling the Prompt
The value of the variable PROMPT_COMMAND is examined just before Bash prints each primary prompt. If PROMPT_COMMAND is set and has a non-null value, then the value is executed just as if it had been typed on the command line.
In addition, the following table describes the special characters which can appear in the prompt variables PS1 to PS4:
\a
A bell character.
\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 escape character.
\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
A newline.
\r
A carriage return.
\s
The name of the shell, the basename of $0 (the portion following the final slash).
\t
The time, in 24-hour HH:MM:SS format.
\T
The time, in 12-hour HH:MM:SS format.
\@
The time, in 12-hour am/pm format.
\A
The 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 + patchlevel (e.g., 2.00.0)
\w
The current working directory, with $HOME abbreviated with a tilde (uses the
$PROMPT_DIRTRIM variable).
\W
The basename of $PWD, with $HOME abbreviated with a tilde.
\!
The history number of this command.
\#
The command number of this command.