perl oneliner

1. Decimal to binary:
perl -wl -e '$num1 = sprintf("%b",15), print $num1;'

2. Decimal to Hexa:
perl -wl -e '$num1 = sprintf("%x",15), print $num1;'

3. Decimal to Octal:
perl -wl -e '$num1 = sprintf("%o",15), print $num1;'

* Further details: perldoc -f sprintf

4. Finding duplicate line:
perl -n -e 'print if $a{$_}++;' filename (or)
perl -wnl -e 'print if $_{$_}++;' filename

5. Removing blank line:
perl -wnl -e 'print unless /^$/;' filename

6. Numbering all the lines:
perl -wnl -e 'print $_= "$. $_";' passwd


7. Print the number of lines of file(s) that match a pattern:
 perl -wnl -e '$x++ if /amit/; END {print $x+0};' file1  file2

7. example:
perl -wnl -e '$x++ if /amit/; END {print $x+0};' test
3
$cat test
amit amit
amit amit
mund mund
amit mund

8 . printing the total number of a match:
perl -waln -e '$t += /amit/ for @F; END { print $t }' test
5
$cat test
amit amit
amit amit
mund mund
amit mund

 9. printing the unix time:
perl -wl -e 'print time;'
1405679195

10. printing localtime:
perl -wl -e 'print $curTime if $curTime=localtime;'
Fri Jul 18 15:57:34 2014

perl -wl -e 'print localtime;'
41561518611451980

l$ perl -le 'print scalar gmtime'
Fri Jul 18 10:29:56 2014

$ perl -le 'print scalar localtime'
Fri Jul 18 16:00:14 2014

11. Factorial of 6:
perl -MMath::BigInt -le 'print Math::BigInt->new(6)->bfac()'
720

12. print a..z:



perl -le 'print join ",", ("a".."z");'

13. print 1..1000:
perl -le 'print join ",", ("1".."1000");'