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Linux System Administration
book

Linux System Administration

by Tom Adelstein, Bill Lubanovic
March 2007
Intermediate to advanced content levelIntermediate to advanced
304 pages
11h 12m
English
O'Reilly Media, Inc.
Content preview from Linux System Administration
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Chapter 10: Scripting
Python has an equivalent to Perl’s getpwent function that enables us to restrict the
search to the field that contains names. Save the following script as finduser.py:
#!/usr/bin/python
import re, sys, pwd
pattern = "(?i)" + sys.argv[1]
for line in pwd.getpwall( ):
if re.search(pattern, line.pw_gecos):
print line
Now let’s see how it works:
admin@server1:~$ ./finduser.py alf
('adedarc', 'x', 501, 501, 'Alfredo de Darc', '/home/adedarc', '/bin/bash')
In this script, the line we printed was a Python list rather than a string, and it was
pretty-printed. To print the line in its original format, use this:
#!/usr/bin/python
import re, sys, pwd
pattern = "(?i)" + sys.argv[1]
for line in pwd.getpwall( ):
if re.search(pattern line.pw_gecos):
print ":".join(["%s" % v for v in line])
The last line is needed to turn each field into a string (pw_uid and pw_gid are inte-
gers) before joining them into one long, colon-separated string. Although Perl and
PHP let you treat a variable as a string or a number, Python is stricter.
The final step is to restrict the searches to accounts with uid > 500:
#!/usr/bin/python
import re, sys, pwd
pattern = "(?i)" + sys.argv[1]
for line in pwd.getpwall( ):
if line.pw_uid > 500 and re.search(pattern line.pw_gecos):
print ":".join(["%s" % v for v in line])
Choosing a Scripting Language
The choice of a programming language, like the choice of a text editor ...
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Publisher Resources

ISBN: 9780596009526Supplemental ContentCatalog PageErrata