commit 6c77854960fd156317977d4e257c162cff35f2b2
parent d7bd99706263b7dc93fdb92cfebafda805850586
Author: spacehobo <spacehobo@web>
Date: Fri, 15 May 2026 08:22:04 +0200
New, more dynamic version
Diffstat:
| M | spacehobo.mdwn | | | 54 | ++++++++++++++++++++++++++++++++++++------------------ |
1 file changed, 36 insertions(+), 18 deletions(-)
diff --git a/spacehobo.mdwn b/spacehobo.mdwn
@@ -2,27 +2,45 @@
Hey, check out my neat `bash` prompt:
- GIT_PS1_SHOWCOLORHINTS='y'
- GIT_PS1_SHOWDIRTYSTATE='y'
- GIT_PS1_SHOWSTASHSTATE='y'
- GIT_PS1_SHOWUNTRACKEDFILES='y'
- GIT_PS1_DESCRIBE_STYLE='contains'
- GIT_PS1_SHOWUPSTREAM='auto'
-
- _noop[0]='array accesses turn 0/nonzero into defined/undef!'
- PS1='\[\e[$(($?==0?1:5));$(($?==0?0:91))m\]\$\[\e[0m\] ' # $?-coloured $
- PS1='$(__git_ps1 "\[\e[1;33m\]{%s\[\e[1;33m\]}")'$PS1 # Gold git
- PS1='\[\e[1;34m\]\w'$PS1 # Blue CWD
- PS1='\[\e[1;33m\]:'$PS1 # Gold colon
- PS1='\[\e[1;32m\]\h'$PS1 # Green hostname
- PS1='\[\e[1;33m\]@'$PS1 # Gold at-sign
- PS1='\[\e[1;35m\]\u'$PS1 # Purple username
- PS1='\[\e[1;36m\]${debian_chroot:+($debian_chroot)}'$PS1 # Cyan chroot
- PS1='${_noop[$((\j==0))]:+\[\e[1;33m\][\j]}'$PS1 # gold nonzero jobs
- PS1='${_noop[$(($?==0))]:+\[\e[1;91m\]($?)}'$PS1 # Red nonzero $?
+```
+GIT_PS1_SHOWCOLORHINTS='y'
+GIT_PS1_SHOWDIRTYSTATE='y'
+GIT_PS1_SHOWSTASHSTATE='y'
+GIT_PS1_SHOWUNTRACKEDFILES='y'
+GIT_PS1_DESCRIBE_STYLE='contains'
+GIT_PS1_SHOWUPSTREAM='auto'
+
+_noop[0]='array accesses turn 0/nonzero into defined/undef!'
+declare -A _session
+_session["tty"]='array accesses turn tty/* into defined/undef!'
+PS1='\[\e[$(($?==0?1:5));$(($?==0?0:91))m\]\$\[\e[0m\] ' # $?-coloured $
+PS1='$(__git_ps1 "\[\e[1;33m\]{%s\[\e[1;33m\]}")'$PS1 # Gold git
+PS1='\[\e[1;34m\]\w'$PS1 # Blue CWD
+PS1='${SSH_CONNECTION:+\[\e[1;32m\]\h\[\e[1;33m\]:}'$PS1 # Green hostname, gold :
+PS1='${_session[$XDG_SESSION_TYPE]:+\[\e[1;35m\]\u${SUDO_USER:+\[\e[1;91m\]($SUDO_USER)}\[\e[1;33m\]@}'$PS1 # Purple username
+PS1='${debian_chroot:+\[\e[1;36m\]($debian_chroot)}'$PS1 # Cyan chroot
+PS1='${_noop[$((\j==0))]:+\[\e[1;33m\][\j]}'$PS1 # gold nonzero jobs
+PS1='${_noop[$(($?==0))]:+\[\e[1;91m\]($?)}'$PS1 # Red nonzero $?
+```
The prompt environment is fairly limited. It can do parameter expansion, reference expansion, arithmetic expansion, and a couple other neat tricks. You can shell out, but if you do that overwrites the variable that contains the exit code of the last program you ran (`$?`). Tools such as the `__git_ps1` hacks do their best to only use features of bash that work internally to bash itself.
This prompt uses the `_noop` array (with only `${_noop[0]}` defined) to turn arithmetic expressions into defined/undefined responses. This lets us use some of the brace-expansion features to specify alternate output, so we can display the error code or number of jobs in the background *only* if they're non-zero, and we can style them with a high degree of freedom.
+It does a similar trick with a string-indexed associative array, and only displays the hostname if the `$XDG_SESSION_TYPE` is `"tty"` (which happens in `ssh` or `sudo` sessions). It dynamically displays the `$SUDO_USER` if that is available.
+
+What this means is that on your local desktop system, when you log in, your prompt is merely:
+
+ ~$
+
+But the same prompt on a remote system will show the more common:
+
+ user@hostname:~$
+
+And if you are in a chroot with background processes looking at a git repo after a command that exited with an error code of `1`:
+
+ (1)[2](thechroot)user@hostname:~{main $%}$
+
+with coloured styling information on all the various parts.
+
I just think it's neat!
