PERL or AWK One-Liners

If used in a script, NOT at the command line, change the ' to ".
It will NOT work with single ticks(') in a script ONLY double (")!!!!
 

1. Split a file every other line
   perl -ne 'print if (++$x)%2' file1 > file2
2. Connect each pair of lines together perl -pe 'if ($. %2){ chomp }else{ s/^/ = / }' file
3. perl -pi.bak -e 'tr/A-Z/a-z/' <filename>
   changes all letters to lowercase in <filename> AND
   saves the original as <filename>.bak
    
   
4. perl -pi.bak -e 's/<original string>/<replacement string>/' <filename1> ... <filenamen>
   changes all the <original string> to <replacement string> IN the
   files <filename1> ... <filenamen> AND
   saves the originals with a .bak extention
    
   
5. perl -e "print join(\"\n\", @INC);"
   Reports what is in the include path
   • The following two methods may be used to append to Perl's @INC array:
     1. Add the directory to the PERL5LIB environment variable.
     2. Add use lib 'directory'; in your Perl script.
   
    
   
6. Add whitespace (pad) every line in a file

   #!/usr/bin/perl
   if ( $#ARGV != 1 ) {
     print "USAGE: </usr/local/bin/>AddTrailingWS.pl <filename> <line length>\n";
   } else {
     $filename = $ARGV[0];
     $maxline  = $ARGV[1];
     system ("mv $filename $filename.BAK");
     open (infile, "$filename.BAK");
     open (outfile,"> $filename");
     while (<infile>) {
       chop;
       $linelen = length;
       $addto   = $maxline-$linelen;
       if ( $linelen >= $maxline ) {
         print outfile "$_\n";
       } else {
         print outfile "$_";
         for ( 1..$addto ) {
           print outfile " ";
         }
           print outfile "\n";
       }
     }
     close(infile);
     close(outfile);
   }

• Kill ALL a users processes.,
  kill -9 `ps -ef |grep <userid> |awk '{ print $2; }'`