Agmeyer: Outline!

2009-10-22T23:05:00Z

Outline!

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<pre>
1. default prompt "\u@\h:\w\$ "
\u username
\h hostname
\w current working directory
\$ # if UID is 0 (root), $ otherwise
2. Pretty colors! \[ and \] keep bash from using the enclosed text in prompt-length calculations
\e[XX;YYm for color, XX is foreground, YY is background. ;1 gives bold foreground, background unnecessary
if default desired
\e[0m resets to default, useful at end of prompt.

Foreground
30 black
31 red
32 green
33 yellow
34 blue
35 purple
36 teal
37 white

Background
40 black
41 red
42 green
43 yellow
44 blue
45 purple
46 teal
47 white
"\[\e[32;1m\]\u@\h:\w\$ \[\e[0m\]" all green
"\[\e[31;1m\]\u\[\e[0m\]@\[\e[33;1m\]\h\[\e[0m\]:\[\e[36;1m\]\w\[\e[32;1m\]\$ \[\e[0m\]" red user, yellow
hostname, teal cwd, green UID symbol
3. Informative but kind of bulky and boring. In .bashrc, we can test if we are in an xterm or not using:
if [ "$TERM" = "linux" ]
If we are, let us put some information up in the xterm titlebar, using the escape sequences "\[\e]2;" "\a"
if [ "$TERM" = "linux" ]
then
export PS1="\[\e[32;1m\]\u@\h:\W\$ \[\e[0m\]"
else
export PS1="\[\e]2;\u@\h:\W\a\e[32;1m\]\$\[\e[0m\] "
fi
Puts username, host, and base of cwd in titlebar, and leaves the UID symbol as prompt in green
4. Scripts! So, if we have scripts that produce output without newlines, we can include them in our prompt by
enclosing the call in $()
Battery status is useful on laptops, so we have a script that puts percentage and status (charging,
discharging, or charged) in a compact form, and colors the percentage based on number (red under
15%, yellow under 30%, green else
"[ \$(/home/agmlego/bin/battery-status) ] \[\e]2;\u@\h:\W\a\e[32;1m\]\$\[\e[0m\] " Battery status followed
by UID symbol in green, username/host/cwd is in titlebar
5. Further customization:
\a an ASCII bell character (07)
\d the date in "Weekday Month Date" format (e.g., "Tue May 26")
\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
\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
\W the basename of the current working directory
\! 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
\[ begin a sequence of non-printing characters, which could be used to embed a terminal control
sequence into the prompt
\] end a sequence of non-printing characters
</pre>

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Agmeyer: Outline!