Python development masterclass

Checking for root user
Some commands only work in root mode. So it will be very helpful if we can check whether the current user is root or not. The following script performs this job. Root is associated with User ID (UID) 0. Hence we are checking for that value to determine who is a root user.

Code for: checkroot.py

@description: Check for root user
import os
if os.getuid() == 0:
 print(“You are a root user !”)
else:
 print (“You are a regular guy .”)
@

@output
kunal@Dell-Work:~/python$ python checkroot.py
You are a regular guy .
kunal@Dell-Work:~/python$ sudo python checkroot.py
You are a root user !
@

Process information
Occasionally a system administrator might need to look into the details of a process that is causing problems. In order to do this we will make use of the commands module which contains wrapper functions for os.popen() which take a system command as a string and return any output generated by the command and, optionally, the exit status. In this case we are running the ps command and then formatting the output of ps according to our needs. This will only work on UNIX systems as we are making use of ps.

Code for:psinfo.py

@Description: Process Information
import commands, os, string

myps = raw_input(“Enter the Process Name: “)

result = commands.getoutput(“ps -ef|grep “ + myps)
psinfo = string.split(result)

print “\n\
Terminal:\t\t”, psinfo[5], “\n\
Owner:\t\t\t”, psinfo[0], “\n\
Process ID:\t\t”, psinfo[1], “\n\
Parent process ID:\t”, psinfo[2], “\n\
Time started:\t\t”, psinfo[4]
@

@output:
kunal@Dell-Work:~/python$ python psinfo.py
Enter the Process Name: konsole

Terminal:               pts/0
Owner:                  kunal
Process ID:             1977
Parent process ID:      1
Time started:           14:30
@

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