Shorten very long dir name in bash prompt

Question

How to get from this prompt

~/this/is/a-very-very-long-directory-name/dir

to this

~/this/is/a-ver...name/dir

in a bash prompt?

So shorten directory names longer than nn (20+) characters to something like xxxx...xxxx

note for possible duplicate: I want to shorten a long dir name, not a long path/to/dir

Possible duplicate of [bash prompt with abbreviated current director including dot files?](https://unix.stackexchange.com/questions/55930/bash-prompt-with-abbreviated-current-director-including-dot-files) — Daniele Santi, Dec 27 '18 at 15:09
Hello @JuTutt. The possible duplicate also shortens a directory name, not a path. That being said, I think your question is more general than the linked one -- and also the answer is more complex (pre and post match). That's why I'm opposing the duplicate vote. — Sebastian, Dec 28 '18 at 21:15

score 4 · Accepted Answer · answered Dec 27 '18 at 15:19

You'll need to use something like sed, bash doesn't have any builtin method.

 d='~/this/is/a-very-very-long-directory-name/with_another_very_long_name/and-here-is-yet-another-one'
# or, d=$(pwd)
e=$( echo "$d" | sed -E 's#([^/]{4})[^/]{13,}([^/.]{3})#\1...\2#g' )
echo "$e"

~/this/is/a-ve...ame/with...ame/and-...one

On the other hand, you may want to throw a newline into your prompt. I use something like this:

PS1='\u@\h:\w\n\$ '

which would look like

jackman@myhost:~/this/is/a-very-very-long-directory-name/with_another_very_long_name/and-here-is-yet-another-one
$ _

score 0 · Answer 2 · answered Dec 27 '18 at 16:25

With shell's "parameter expansion", try

d='~/this/is/a-very-very-long-directory-name/with_another_very_long_name/and-here-is-yet-another-one'
IFS=/
for DIR in $d
  do    [ ${#DIR} -gt 8 ] &&    { TMP=${DIR%%${DIR#????}}
                                  DIR=$TMP...${DIR##${DIR%????}}
                                }
        NEW="$NEW${NEW:+/}$DIR"
  done
echo "$NEW"
~/this/is/a-ve...name/with...name/and-...-one

Save and restore IFS if need be. Running in a subshell won't work as you want to access the NEW variable afterwards (unless you use "command substitution"...).

Shorten very long dir name in bash prompt

2 Answers2