Perl capture between single quotes in a one-liner

Question

I am trying to print out the text that is surrounded by single quotes.

/bin/bash -lc '/home/CASPER_REPORTS/scripts/CASPER_gen_report.sh CASPER_1'
/bin/bash -lc '/home/CASPER_REPORTS/scripts/CASPER_gen_report.sh CASPER_1A'
/bin/bash -lc '/home/CASPER_REPORTS/scripts/CASPER_gen_report.sh CASPER_2'
/bin/bash -lc '/home/CASPER_REPORTS/scripts/CASPER_gen_report.sh CASPER_3'
/bin/bash -lc '/home/CASPER_REPORTS/scripts/CASPER_gen_report.sh CASPER_3A'

The Boolean one I guess means that perl sees the string.

$ cat /tmp/casper_reports | perl -nle 'print /'.*'/'
1
1
1
1
1

However when I try and capture it with the parenthesis it throws an error

$ cat /tmp/boobomb | perl -nle 'print /'(.*)'/'
-bash: syntax error near unexpected token `('

The syntax for escaping a `'` is insane, so if you can avoid it, ^ — zzxyz, Jan 10 '18 at 00:09
As an aside, lose the [useless use of `cat`](https://stackoverflow.com/questions/11710552/useless-use-of-cat) — tripleee, Jan 10 '18 at 05:30

score 5 · Accepted Answer · edited Jan 10 '18 at 05:29

5

In the Bash and Zsh shells, you can use $'' to allow escaped single quotes.

echo $'I wouldn\'t'

This also keeps $1 from being interpreted by bash and available to perl too.

perl -nle $'print $1 if /\'(.*)\'/' < /tmp/boobomb

also see https://unix.stackexchange.com/questions/30903/how-to-escape-quotes-in-shell

edited Jan 10 '18 at 05:29

tripleee

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answered Jan 10 '18 at 00:20

Will

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This form of escaping does not work in `csh`, `dash`, or `sh`. May be worth noting that this is a `bash`/`zsh` -specific feature. – Silvio Mayolo Jan 10 '18 at 01:05

zdim · Answer 2 · 2019-07-24T08:58:43.010

5

Use hex for the single quote (27) via hexadecimal escape, so \x27

perl -wnE'say $1 if /\x27(.*)\x27/' input.txt

This assumes a single pair of single quotes, per shown sample data on which it was tested.

edited Jul 24 '19 at 08:58

answered Jan 10 '18 at 05:20

zdim

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Perl capture between single quotes in a one-liner

2 Answers2