Introduction to Python (by Ilan Schnell)

Simple File Parsing:

Suppose we want parse the /etc/passwd file,

root:x:0:0:root:/root:/bin/bash
sshd:x:71:65:SSH daemon:/var/lib/sshd:/bin/false
ilan:x:500:100:Ilan Schnell:/home/ilan:/bin/tcsh
...

and create a dictionary of the uid mapping to the username.

#!/usr/bin/python

uidmap={}
for line in file('/etc/passwd'):
    lst = line.split(':')
    uidmap[lst[2]] = lst[0]

while True:
    print uidmap[raw_input('Please enter uid: ')]

Program in action:

$ ./uidmap.py 
Please enter uid: 500
ilan
Please enter uid: 71
sshd