Buongiorno,
I am trying to grep all the patterns that look like: [00 0] or [ 0000] but not [00] or [0000] : there has to be at least one space.
Naively, I thought that
grep -P '\[.* .*\]'
would do it ; when I copy paste the regex in regex101 with some test cases, I get the following:
unmatched:
0 0
000
[00]
[0]
[00]
matched:
[0 0]
[ 0]
[0 ]
[ 0 ]
[ 0 ]
which is exactly what I want.
But grep seems to match also the things between brackets but with no space:
[00]
[0]
[00]
What am I missing ?
\[0* 0*\]
seems to work but I'm going to have cases where it's not only 0...
This grep would work with BRE (basic regex), it doesn't require ERE (extended regex) or experimental -P (perl regex):
grep '\[[^] ]* [^]]*]' file
[0 0]
[ 0]
[0 ]
[ 0 ]
[ 0 ]
If you have only zeroes and spaces inside the [...] then try:
grep '\[0* [0 ]*]' file
RegEx Details:
\[: Match a [[^] ]*: Match 0 or more of any chars that are not ] and space : Match a space[^]]*: Match 0 or more of any chars that are not ]]: Match a ]Problem with .* is that it matches 0 or more of any character except a line break. It won't stop at ].