(features.info)Printing a Prompt

Controlling the Prompt
======================

   The value of the variable `$PROMPT_COMMAND' is examined just before
Bash prints each primary prompt.  If it is set and non-null, then the
value is executed just as if you had typed it on the command line.

   In addition, the following table describes the special characters
which can appear in the `PS1' variable:

`\t'
     the time, in HH:MM:SS format.

`\d'
     the date, in "Weekday Month Date" format (e.g. "Tue May 26").

`\n'
     newline.

`\s'
     the name of the shell, the basename of `$0' (the portion following
     the final slash).

`\w'
     the current working directory.

`\W'
     the basename of `$PWD'.

`\u'
     your username.

`\h'
     the hostname.

`\#'
     the command number of this command.

`\!'
     the history number of this command.

`\nnn'
     the character corresponding to the octal number `nnn'.

`\$'
     if the effective uid is 0, `#', otherwise `$'.

`\\'
     a backslash.

`\['
     begin a sequence of non-printing characters.  This could be used to
     embed a terminal control sequence into the prompt.

`\]'
     end a sequence of non-printing characters.