Remove digits from end of string

Question

I want to remove digits from end of a string.

Example:

 string123
 example545

Output:

string
example

Don't know why this was downvoted. Some people here are certainly pretentious. — Ken - Enough about Monica, Jul 19 '18 at 15:16
@HH probably because it looks a lot like a homework question, with no apparent effort made (or at least demonstrated) to find the answer. They get cranky about that. Of course now I'm trying to do something similar, and my search led me here — Doktor J, Oct 15 '20 at 15:07

Benjamin W. · Answer 1 · 2018-01-12T04:54:02.913

13

Without external tools, just parameter expansion and extended globbing:

$ shopt -s extglob
$ var=string123
$ echo "${var%%+([[:digit:]])}"
string
$ var=example545
$ echo "${var%%+([[:digit:]])}"
example

The +(pattern) extended glob pattern is "one or more of this", so +([[:digit:]]) is "one or more digits".

The ${var%%pattern} expansion means "remove the longest possible match of pattern from the end of var.

edited Jan 12 '18 at 04:54

answered Jan 07 '18 at 02:14

Benjamin W.

1

How do you disable the extglob again? – Hubert Grzeskowiak Aug 16 '18 at 10:55
2

@Hubert `shopt -u extglob` – Benjamin W. Aug 16 '18 at 12:24

Thomas Smyth - Treliant · Accepted Answer · 2018-01-06T20:05:07.387

6

Provided you have no other digits anywhere else in the string you can do:

echo string123 | sed 's/[0-9]//g'
string

And only the end of the string:

echo S1tring123 | sed 's/[0-9]\+$//'
S1tring

Where $ indicates the end of the line.

edited Jan 06 '18 at 20:05

answered Jan 06 '18 at 19:52

what if string contains say " S1tring123 " I wish to only remove the ending digits, so remove digits up until alpha type of thing – jake reading Jan 06 '18 at 19:55
2

Well it is important in the first one as that would remove only the first digit :) – PesaThe Jan 06 '18 at 20:04

score 2 · Answer 3 · answered Jan 06 '18 at 22:03

2

With grep

echo S1tring123 | grep -o '.*[^0-9]'

answered Jan 06 '18 at 22:03

ctac_

score 2 · Answer 4 · answered Jan 07 '18 at 02:09

2

awk '{sub(/[0-9]+$/,"")}1' file

string
example

answered Jan 07 '18 at 02:09

Claes Wikner

score 1 · Answer 5 · answered Jan 06 '18 at 20:41

1

Not sure to fully understand your requirements, but try:

sed 's/[0-9]*\([^[:alnum:]]*\)$/\1/' file

or perhaps:

sed 's/[0-9]*\([^0-9]*\)$/\1/' file

answered Jan 06 '18 at 20:41

5 Answers5