asked on

find matching pattern in perl using command line and output matching itself (if found).

How to find match in perl using command line?
Okay, I can even substitute using

perl -i.bak -pe 's/pattern1/pattern2/g' inputFile

How to just find match and output catches?
perl -pe 'if ($_ =~ m/$.+?src(.+?)^/) {print "$1\n"}' inputFile

ozo

perl -pe 'print if /pattern1/' inputFile
perl -lpe 'print $1 if /src(.+?)/' inputFile

Nusrat Nuriyev

ASKER

perl -pe 'print if /pattern1/' inputFile

It outputs all lines no matter what pattern is given.

Nusrat Nuriyev

ASKER

perl -lpe 'print $1 if /src(.+?)/' inputFile

also outputs all and whole lines , no matter of pattern

Generally
perl -pe '' inputFile
outputs all content of file is
Is that expected behavior?
As I understand if no code, then it just iterates but should not output.

the behaviour of -p:

while (<>) {
... # your script
} continue {
print or die "-p destination: $!\n";
}

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ozo

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Nusrat Nuriyev

ASKER

Notice the use of the empty file input operator, which will read all of the files given on the command line a line at a time. Each line of the input files will be put, in turn, into $_ so that you can process it. As a example, try:

$ perl -n -e 'print "$. - $_"' file

This gets converted to:

LINE:
while (<>) {
print "$. - $_"
}

This code prints each line of the file together with the current line number.

The -p option makes that even easier. This option always prints the contents of $_ each time around the loop. It creates code like this:

LINE:
while (<>) {
# your code goes here
} continue {
print or die "-p destination: $!\n";
}