Parse command line argument

Question

Some of you might know this script, it's called hash-identifier. When it is run the user is prompted to enter a hash. I want to pass the hash as a command line argument so that the script can be executed like that:

hash-identifier d14a028c2a3a2bc9476102bb288234c415a2b01f828ea62ac5b3e42f

I found out that I need to import sys and getopt but I have never used python before so any suggestions would be helpful.

Answer 1

the preferred method is to use argparse:

#!/usr/bin/env python
import argparse
if __name__ == "__main__":
 parser = argparse.ArgumentParser(description="Does something with a hash");
 parser.add_argument("hash", metavar="HASH", help="the hash to do things with?");
 args = parser.parse_args();
 hash = args.hash;
 # Use the hash...
 print(hash);

But using argparse might be a bit overkill for your needs, it may be simpler for you to do this:

#!/usr/bin/env python
import sys
if __name__ == "__main__":
 if len(sys.argv) != 2: # first is program name, second is argument
 print("USAGE: %s HASH"%(sys.argv[0],));
 sys.exit();
 hash = sys.argv[1];
 # Use the hash...
 print(hash);

Answer 2

Ok, after I imported sys, the only thing I need to do is pass the sys.argv to the variable being printed. Example:

variable = sys.argv
print variable

Answer 3

You can either use sys.argv[0] to get the first command line argument to the script. Or the argparse module if you want more options.