perl: add PCRE one liner example (#3129)

2019-09-24 06:00:09 -07:00
parent 66dd8e6acc
commit ec2213a34a
1 changed files with 4 additions and 0 deletions
--- a/pages/common/perl.md
+++ b/pages/common/perl.md
@@ -30,3 +30,7 @@
 - Run a multi-line find/replace expression on a file, and save the result in another file:

 `perl -p0e 's/{{foo\nbar}}/{{foobar}}/g' {{input_file}} > {{output_file}}`
+
+- Run a regular expression on `stdin`, printing out first capture group for each line:
+
+`cat {{path/to/input_file}} | perl -nle 'if (/.*({{foo}}).*/) {print "$1"; last;}'`