Added 3 new functions:
Print the current unix timestamp
Run the script with no arguments
e.g:
joe@phobos ~/blatech/unixtime $ ./unixtime.pl
1499865953
Convert from time since the Unix epoch, given in milliseconds
Run the script with a timestamp in milliseconds, and add a second argument "ms"
e.g:
joe@phobos ~/blatech/unixtime $ ./unixtime.pl 1499865571123 ms
Wed Jul 12 14:19:31:123 BST 2017
Print the current time since the Unix epoch in milliseconds
Run the script only with the argument "ms"
e.g:
joe@phobos ~/blatech/unixtime $ ./unixtime.pl ms
1499866043745