How to do a grep regex search for single-quotes?

Question

How do you use grep to do a text file search for a pattern like ABC='123'?

I'm currently using:

grep -rnwi some/path -e "ABC\s*=\s*[\'\"][^\'\"]+[\'\"]"

but this only finds text like ABC="123". It misses any instances that use single-quotes. What's wrong with my regex?

for BRE, you would need to use \+ or use the current regex with -E option to use ERE — Sundeep
– Sundeep, Commented Feb 9, 2017 at 1:59
@Sundeep + is not in BRE at all, but GNU grep BRE supports it as an extension. — Benjamin W.
– Benjamin W., Commented Feb 9, 2017 at 16:50

codeforester · Accepted Answer · 2017-02-09 02:02:58Z

You are using a PCRE. So, you need the -P flag. So, use this:

grep -rnwi some/path -P "ABC\s*=\s*[\'\"][^\'\"]+[\'\"]"

We don't need a \\ for single quotes inside the character classes. So, your regex can also be written as:

"ABC\s*=\s*['\"][^'\"]+['\"]"

Input file:

ABC="123" ABC='123'

Run grep with your PCRE:

grep -P "ABC\s*=\s*['\"][^'\"]+['\"]" input.txt

Output:

ABC="123" ABC='123'

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