STRING-MATCH(1)

NAME
string-match - match substrings

SYNOPSIS

string match [(-a | --all)] [(-e | --entire)] [(-i | --ignore-case)] [(-r | --regex)] [(-n | --index)] [(-q | --quiet)] [(-v | --invert)] PATTERN [STRING...]

DESCRIPTION

string match tests each STRING against PATTERN and prints matching substrings. Only the first match for each STRING is reported unless -a or --all is given, in which case all matches are reported.

If you specify the -e or --entire then each matching string is printed including any prefix or suffix not matched by the pattern (equivalent to grep without the -o flag). You can, obviously, achieve the same result by prepending and appending * or .* depending on whether or not you have specified the --regex flag. The --entire flag is simply a way to avoid having to complicate the pattern in that fashion and make the intent of the string match clearer. Without --entire and --regex, a PATTERN will need to match the entire STRING before it will be reported.

Matching can be made case-insensitive with --ignore-case or -i.

If --index or -n is given, each match is reported as a 1-based start position and a length. By default, PATTERN is interpreted as a glob pattern matched against each entire STRING argument. A glob pattern is only considered a valid match if it matches the entire STRING.

If --regex or -r is given, PATTERN is interpreted as a Perl-compatible regular expression, which does not have to match the entire STRING. For a regular expression containing capturing groups, multiple items will be reported for each match, one for the entire match and one for each capturing group. With this, only the matching part of the STRING will be reported, unless --entire is given.

If --invert or -v is used the selected lines will be only those which do not match the given glob pattern or regular expression.

Exit status: 0 if at least one match was found, or 1 otherwise.

EXAMPLES

  Match Glob Examples

>_ string match '?' a
a
>_ string match 'a*b' axxb
axxb
>_ string match -i 'a??B' Axxb
Axxb
>_ echo 'ok?' | string match '*\\?'
ok?
# Note that only the second STRING will match here.
>_ string match 'foo' 'foo1' 'foo' 'foo2'
foo
>_ string match -e 'foo' 'foo1' 'foo' 'foo2'
foo1
foo
foo2
>_ string match 'foo?' 'foo1' 'foo' 'foo2'
foo1
foo
foo2

  Match Regex Examples

>_ string match -r 'cat|dog|fish' 'nice dog'
dog
>_ string match -r -v "c.*[12]" {cat,dog}(seq 1 4)
dog1
dog2
cat3
dog3
cat4
dog4
>_ string match -r '(\\d\\d?):(\\d\\d):(\\d\\d)' 2:34:56
2:34:56
2
34
56
>_ string match -r '^(\\w{{2,4}})\\g1$' papa mud murmur
papa
pa
murmur
mur
>_ string match -r -a -n at ratatat
2 2
4 2
6 2
>_ string match -r -i '0x[0-9a-f]{{1,8}}' 'int magic = 0xBadC0de;'
0xBadC0de

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