The command md5 calculates an unique string for each input given as argument using the md5 algorithm. 
md5 [flags] [arg1] [arg2]
Where [flags] are the (optional) md5 flags, read below for more info, and [arg1], [arg2] are the path for files or string (depending on the flags). Example: md5 sum of the string Hello there 
md5 -s "Hello there"
    MD5 ("Hello there") = e8ea7a8d1e93e8764a84a0f3df4644de

Flags

  • -s: computes the md5 sum of a string instead of a file
  • -q: prints the md5 sum without the file or string name
  • -r: reverses the format of the output