I have a file like:
abc WANT THIS
def NOT THIS
ghijk WANT THIS
lmno DO NOT LIKE
pqr WANT THIS
...
From which I want to extract:
abc
ghijk
pqr
When I apply the following:
(Select-String -Path $infile -Pattern "([^ ]+) WANT THIS").Matches.Groups[1].Value >$outfile
It only returns the match for the first line:
abc
(adding -AllMatches did not change the behaviour)
You may use
Select-String -path $infile -Pattern '^\s*(\S+) WANT THIS' -AllMatches | Foreach-Object {$_.Matches} | Foreach-Object {$_.Groups[1].Value} > $outfile
The ^\s*(\S+) WANT THIS pattern will match
^ - start of a line\s* - 0+ whitespaces(\S+) - Group 1: one or more non-whitespace chars WANT THIS - a literal substring.Now, -AllMatches will collect all matches, then, you need to iterate over all matches with Foreach-Object {$_.Matches} and access Group 1 values (with Foreach-Object {$_.Groups[1].Value}), and then save the results to the output file.
Re-reading the code, its matching them all, but only writing the value of the first match (doh!):
(Select-String -Path $scriptfile -Pattern "([^ ]+) WANT THIS").Matches.Groups.Value >$tmpfile
OTOH, it appears that the "captures" in the pattern output object also contain the "non-captured" content!!!!
pqr WANT THIS line, since it starts with a whitespace.
Select-String -path $infile -Pattern '^\s*(\S+) WANT THIS' -AllMatches | Foreach-Object {$_.Matches} | Foreach-Object {$_.Groups[1].Value}