OT: unix newbie questions

[Fredrik Lundh]

Carlos Lopez wrote:

> Please help i am losing my mind ... UNIX Newbee
> 
> *23. How do you add a line to the end of an existing file "myfile" with 
> date stamp. (1) *

 >>> f = open("myfile", "a+")
 >>> f.write(datestamp)
 >>> f.close()

> *24. Display recent 10 java files, (with *.java extension) , in 
> descending order by time, latest to oldest time. (1) *

 >>> files = sorted(glob.glob("*.py"), key=os.path.getmtime)[-10:]
 >>> files.reverse()

> *25. How do you set only read permissions to user, group and others in 
> octal mode for a file "myfile.txt" ? (2)

 >>> os.chmod("myfile.txt", 0444) # note the leading zero

> *26. You observed that some of your group members are fiddling with your 
> file  "myfile" and you wanted to remove the read permission to your 
> group. How do you do? (1)

 >>> os.chmod("myfile.txt", 0404)

> *28. Here is another long listing of a file. (1)*

> -rw-r----- 1 Y435678 odms 20 Sep 02 17:03 file.txt. ***
> 
> *What are the owner permissions? *

 >>> s = os.stat("urllib.py").st_mode
 >>> if s & stat.S_IREAD: print "READ"
 >>> if s & stat.S_IWRITE: print "WRITE"
 >>> if s & stat.S_IEXEC: print "EXEC"

> *29. The file “users_data” has the following contents :  (1)
> Tom  Smith       7.00  15  105.00
> Rob  Sheryl       8.00 20  160.00
> Ken  Bradman  7.00 13   91.00
> Peter Smith      6.00 15   90.00
> Dennis  Smith   8.00 13  104.00
> Tom  Dave        9.00 12  108.00 *
> 
> *How do you sort the above file and redirect the output to another file 
> called “sortedusers” *

 >>> out = open("sortedusers", "w")
 >>> out.writelines(sorted(open("users_data")))

> *20. What is the command to list files in a directory : (2)

 >>> os.listdir(directory)

or, if you want full path names and glob-style filtering:

 >>> glob.glob(os.path.join(directory, "*"))

</F>