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Diffstat (limited to 'src/tools/bash.md')
| -rw-r--r-- | src/tools/bash.md | 19 |
1 files changed, 19 insertions, 0 deletions
diff --git a/src/tools/bash.md b/src/tools/bash.md index 201a6ad..15f455a 100644 --- a/src/tools/bash.md +++ b/src/tools/bash.md @@ -136,6 +136,25 @@ parse_args -f xxx -c parse_args -f yyy ``` +## Regular Expressions + +Bash supports regular expression matching with the binary operator `=~`. +The match results can be accessed via the `$BASH_REMATCH` variable: +- `${BASH_REMATCH[0]}` contains the full match +- `${BASH_REMATCH[1]}` contains match of the first capture group + +```bash +INPUT='title foo : 1234' +REGEX='^title (.+) : ([0-9]+)$' +if [[ $INPUT =~ $REGEX ]]; then + echo "${BASH_REMATCH[0]}" # title foo : 1234 + echo "${BASH_REMATCH[1]}" # foo + echo "${BASH_REMATCH[2]}" # 1234 +fi +``` +> **Caution**: When specifying a `regex` in the `[[ ]]` block directly, quotes will be treated as part of the pattern. +> `[[ $INPUT =~ "foo" ]]` will match against `"foo"` not `foo`! + ## Completion The `complete` builtin is used to interact with the completion system. |