How can I find a specific line in a file using Perl?

Question

I am new to Perl. I want to find a string in some file, and then I want the whole string to contain the string.

Answer 1

perl -ne 'print if m/whatever/' file

Answer 2

• Open file

• Loop while there are lines to read from the file

  2.1 Using regular expressions , check if the string matches the pattern: if ($line =~ /pattern/) .

  2.2 If yes, print string

• Close file.

Answer 3

 if ( !open(LOGFILE, "<myfile.log") ) { print "ERROR: failed to open myfile.log\n";} else { while (<LOGFILE>){ if ($_ =~ /pattern/) { print "found\n"; break; } } close (LOGFILE); }