test for regex in string with a posix shell

Question

how can I test if a string matches a particular string matches regex with a basic (no bash or anything) posix shell script (in an if statement)?

see also: https://stackoverflow.com/q/21115121/537554 – ryenus Apr 05 '18 at 03:46 — ryenus, Apr 05 '18 at 03:46

score 14 · Accepted Answer · answered Feb 29 '16 at 07:33

14

You can use expr command to evaluate regular expression in a POSIX shell:

s='Abc'
expr $s : '^[[:alpha:]]\+'

3

expr returns # of matched characters which is 3 in this case.

answered Feb 29 '16 at 07:33

anubhava

4

Caveat: for `expr`, a ‘^’ is implicitly prepended, also the regex has to be in the basic form. – ryenus Apr 05 '18 at 04:04

1 Answers1