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My First Python script. Trying to find text manipulation

So I am embarking on my first python script.

I want to

1) Take an LVM snapshot
2) Mount it RO under /mnt
3) Use "dump" to create a dumpfile to keep as backup
4) umount /mnt
5) delete the snapshot

This is what I have so far

Code:

#!/usr/bin/python

#

import os, sys, traceback

from subprocess import Popen, PIPE

#

# This is a backup script that just uses "dump"

lvcommand = ('lvs', '--noheadings')

rootvol = Popen(lvcommand, stdout=PIPE, stderr=PIPE)

print rootvol.stdout.readline()

#

##-30-

Which outputs...

Code:

[root@vr12-0801 ~]# python bakup_rhevm.py

  lv_root vg0  -wi-ao--- 268.57g

So far so good (in my book at least :P ...BUT SUGGESTIONS _are_ welcome! )

Now how do I "manipulate" this string? Because I want to take the lv_root into a variable and vg0 into another one and basically run...

Code:

lvcreate --snapshot /dev/vg0/lv_root --name lv_root_snapshot --size 15M

...but before I get ahead of myself :-)

If someone could point me to some good "text manipulation" documentation; that would be helpful :-)

OPTIONAL READING:

Some may ask "why do this in python?"

Answer: I can do this...quite easily actually in shell - but I find learning a new language is "easier" if I can actually do a "real world" problem.

Thanks!

--C

I suggest you are in need of the split() feature
So given you have the string in a variable lvs

Code:

lvs="lv_root vg0  -wi-ao--- 268.57g"

flds=lvs.split()  # splits on whitespace

['lv_root', 'vg0', '-wi-ao---', '268.57g']

outstr="lvcreate --snapshot /dev/%s/%s --name %s_snapshot --size 15M" % (flds[1],flds[0],flds[0])

print outstr

A search engine of your choice is your friend and a search on "Python strings" should give you more of what you are after.

Quote:

Originally Posted by keirvt (Post 4932818)

A search engine of your choice is your friend and a search on "Python strings" should give you more of what you are after.

Perfect; exactly what I was looking for! :D