Programming Forums > Script Programming > Sed and Awk

Thaidog · Aug 15th, 2007, 12:13 PM

Can somebody please give me an example of the sed code that could uncomment a drive mount line in fstab?

Infinite Recursion · Aug 15th, 2007, 1:29 PM

Is it a particular line you are interested in? Are there other commented mounts that you want to exclude? What does your fstab look like?

To remove all # in the file you could do this:

cat fileA | sed 's/#//g' > fileB; mv fileB fileA

If you want a more specific line uncommented, need more info.

Thaidog · Aug 15th, 2007, 5:05 PM

Quote:

Originally Posted by Infinite Recursion

Is it a particular line you are interested in? Are there other commented mounts that you want to exclude? What does your fstab look like?

To remove all # in the file you could do this:

cat fileA | sed 's/#//g' > fileB; mv fileB fileA

If you want a more specific line uncommented, need more info.

There are two lines that need to be uncommented and a few others that need to stay commented.

The two that need uncommenting look like this:

#/dev/sde1 /vmware/tol ext3 nosuid 0 0
#/dev/sdf1 /vmware/sas ext3 nosuid 0 0

Infinite Recursion · Aug 16th, 2007, 10:47 AM

check out regular expressions and/or http://www.student.northpark.edu/pem...d/sed1line.txt

peace_of_mind · Aug 16th, 2007, 11:05 AM

Nice link. Thanks, IR.

Thaidog · Aug 16th, 2007, 3:15 PM

OK. How does this look?

sed 's/\(#\)\(/dev/sde1.*\)/\2/' /etc/fstab

sed 's/\(#\)\(/dev/sdf1.*\)/\2/' /etc/fstab

Infinite Recursion · Aug 16th, 2007, 3:47 PM

My shell responds with:
sed: command garbled: s/\(#\)\(/dev/sde1.*\)/\2/

You need to escape the / character... like this:

sed 's/\(#\)\(\/dev\/sde1.*\)/\2/' /etc/fstab
sed 's/\(#\)\(\/dev\/sdf1.*\)/\2/' /etc/fstab

The only difference is the sde vs sdf... regular expressions would allow you to process them with just one line. But if its a one time execution, save yourself the trouble.

You're welcome PoM...

There is another one for Awk floating around somewhere.

Thaidog · Aug 16th, 2007, 4:15 PM

Quote:

Originally Posted by Infinite Recursion

My shell responds with:
sed: command garbled: s/\(#\)\(/dev/sde1.*\)/\2/

You need to escape the / character... like this:

sed 's/\(#\)\(\/dev\/sde1.*\)/\2/' /etc/fstab
sed 's/\(#\)\(\/dev\/sdf1.*\)/\2/' /etc/fstab

The only difference is the sde vs sdf... regular expressions would allow you to process them with just one line. But if its a one time execution, save yourself the trouble.

You're welcome PoM...

There is another one for Awk floating around somewhere.

It's really just a one time execution. Thanks for the help! One last thing.... would the -i switch be a good idea here? For instance:

sed -i 's/\(#\)\(\/dev\/sde1.*\)/\2/' /etc/fstab

Infinite Recursion · Aug 17th, 2007, 3:16 PM

It works without the -i. I would leave it as is.

Aug 15th, 2007, 12:13 PM	#1
Thaidog Newbie Join Date: Sep 2004 Posts: 8 Rep Power: 0	Need sed to uncomment fstab file lines. Can somebody please give me an example of the sed code that could uncomment a drive mount line in fstab?

Aug 15th, 2007, 1:29 PM	#2
Infinite Recursion Programming Guru Join Date: Jul 2004 Location: United States Posts: 3,436 Rep Power: 7	Is it a particular line you are interested in? Are there other commented mounts that you want to exclude? What does your fstab look like? To remove all # in the file you could do this: cat fileA \| sed 's/#//g' > fileB; mv fileB fileA If you want a more specific line uncommented, need more info. __________________ http://jasonpowers.net "There are a thousand hacking at the branches of evil to one who is striking at the root."

Aug 16th, 2007, 10:47 AM	#4
Infinite Recursion Programming Guru Join Date: Jul 2004 Location: United States Posts: 3,436 Rep Power: 7	check out regular expressions and/or http://www.student.northpark.edu/pem...d/sed1line.txt __________________ http://jasonpowers.net "There are a thousand hacking at the branches of evil to one who is striking at the root."

Aug 16th, 2007, 11:05 AM	#5
peace_of_mind Professional Programmer Join Date: Sep 2004 Location: Hell if I know most of the time Posts: 435 Rep Power: 4	Nice link. Thanks, IR. __________________ Amateurs built the ark Professionals built the Titanic

Aug 16th, 2007, 3:47 PM	#7
Infinite Recursion Programming Guru Join Date: Jul 2004 Location: United States Posts: 3,436 Rep Power: 7	My shell responds with: sed: command garbled: s/\(#\)\(/dev/sde1.\)/\2/ You need to escape the / character... like this: sed 's/\(#\)\(\/dev\/sde1.\)/\2/' /etc/fstab sed 's/\(#\)\(\/dev\/sdf1.*\)/\2/' /etc/fstab The only difference is the sde vs sdf... regular expressions would allow you to process them with just one line. But if its a one time execution, save yourself the trouble. You're welcome PoM... There is another one for Awk floating around somewhere. __________________ http://jasonpowers.net "There are a thousand hacking at the branches of evil to one who is striking at the root."

Aug 16th, 2007, 3:15 PM	#6
Thaidog Newbie Join Date: Sep 2004 Posts: 8 Rep Power: 0	OK. How does this look? sed 's/\(#\)\(/dev/sde1.\)/\2/' /etc/fstab sed 's/\(#\)\(/dev/sdf1.\)/\2/' /etc/fstab

Aug 17th, 2007, 3:16 PM	#9
Infinite Recursion Programming Guru Join Date: Jul 2004 Location: United States Posts: 3,436 Rep Power: 7	It works without the -i. I would leave it as is. __________________ http://jasonpowers.net "There are a thousand hacking at the branches of evil to one who is striking at the root."

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Programming Forums > Script Programming > Sed and Awk

Need sed to uncomment fstab file lines.