You can use several special characters (indicated by adding a backslash to a variety of letters) to
include different information in your prompt. These can include your terminal number, the date,
and the time, as well as other pieces of information. Table 2-6 provides some examples (you can
find more on the
bash
man page).
TABLE 2-6
Characters to Add Information to the bash Prompt
Special Character
Description
\!
Shows the current command history number. This includes all previous commands
stored for your username.
\#
Shows the command number of the current command. This includes only the
commands for the active shell.
\$
Shows the user prompt ($) or root prompt (#), depending on which user you are.
\W
Shows only the current working directory base name. For example, if the current
working directory was /var/spool/mail, this value simply appears as mail.
\[
Precedes a sequence of nonprinting characters. This can be used to add a terminal
control sequence into the prompt for such things as changing colors, adding blink
effects, or making characters bold. (Your terminal determines the exact sequences
available.)
\]
Follows a sequence of nonprinting characters.
\\
Shows a backslash.
\d
Displays the day name, month, and day number of the current date. For example:
Sat Jan 23.
\h
Shows the hostname of the computer running the shell.
\n
Causes a newline to occur.
\nnn
Shows the character that relates to the octal number replacing nnn.
\s
Displays the current shell name. For the bash shell, the value would be bash.
\t
Prints the current time in hours, minutes, and seconds (for example, 10:14:39).
\u
Prints your current username.
\w
Displays the full path to the current working directory.
If you are setting your prompt temporarily by typing at the shell, you should put the
value of PS1 in quotes. For example, you could type export PS1="[\t \w]\$ " to
see a prompt that looks like this: [20:26:32 /var/spool]$.
To make a change to your prompt permanent, add the value of
PS1
to your
.bashrc
file in your
home directory (assuming that you are using the bash shell). There may already be a
PS1
value in
TIP
TIP
58
Linux First Steps
Part I
