grep regex how to remove single quote

Question

I'd like to get the quoted string from output of lvscan which is :

  ACTIVE            '/dev/mysys/root' [297.46 GiB] inherit

What I've done is to use code below:

lvscan | grep -o "[^']\+\b'"

and what I got is :

/dev/mysys/root'

if I remove the very last single quote, I got three lines:

ACTIVE
/dev/mysys/root
[297.46 GiB] inherit

I also tried:

lvscan | grep -o "[@(^'\+.*)].*\>'"
lvscan | grep -o "[^']\+\>'"

What did I miss here?

Any comments would appreciate. Thank you.

The last line should be: Any comments would be appreciated. Thank you. — Tao Wang, Oct 26 '16 at 15:38

score 2 · Answer 1 · answered Oct 25 '16 at 23:05

2

You can use cut instead of grep:

lvscan | cut -f2 -d\'

answered Oct 25 '16 at 23:05

choroba

thanks a lot, this one worked as well. I think your suggestion would be easier. But vks' answer goes first, so I have to give my acceptance to vks. – Tao Wang Oct 26 '16 at 17:16
Where have you seen such a rule? :-) – choroba Oct 27 '16 at 07:33

score 1 · Accepted Answer · answered Oct 25 '16 at 23:14

1

if you have -P with grep you can use

lvscan | grep -oP "(?<=')[^']+(?=')"

answered Oct 25 '16 at 23:14

vks

can also use `grep -oP "'\K[^']+(?=')"` – Sundeep Oct 26 '16 at 02:44
Obviously, I'm not using Perl, and l'll check it out tomorrow, this. – Tao Wang Oct 26 '16 at 05:49
1

Thanks a lot, vks, this line worked for me, I don't really care whether it's Perl Regex or not. An interesting question still remained though, is there a Basic Regex solution for this? – Tao Wang Oct 26 '16 at 15:33
@TaoWang basic regex can be used like `'([^']*)'` and then grab the group 1 but i have not used that with grep so m not sure – vks Oct 26 '16 at 15:57
`lvscan | grep -Go "'.*'"` is the simplest answer I've tried for Basic Regex if ignoring single quotes pair. – Tao Wang Oct 26 '16 at 17:17
1

The reason I wanna remove quotes is I'd like to print the output to a variable for later use. Insisting on keeping tried is for learning purpose, thanks again. – Tao Wang Oct 26 '16 at 17:25

2 Answers2