Issue
I have a string in a file say:
abc
or
def abc
I want to match abc such that it can either appear at the beginning of the line or after a blank.
I can do it with matching multiple patterns, separating with | like:
/^abc|[[:blank:]]+abc/
But is there some way to include ^ i.e. beginning of the string something like character class.
^ at the beginning of character class would mean negation and other positions would mean just match the caret ('^') character.
Also, in my original case, the string is not just abc, instead it is a string matched with a a complex regex, so I prefer it to be as clean as possible. I am matching this regex inside an awk script. Although I still include bash tag because system() function can still be used within it. Speed doesn't matter much to me in my case, but clarity does.
Solution
Use a capturing group:
(^|[[:blank:]]+)abc
It will match the beginning of the string or a run of blanks. You can drop + if you don't need all blanks preceding abc in your match but the last.
Answered By - oguz ismail Answer Checked By - Clifford M. (WPSolving Volunteer)