Need to update some file abc in my script xyz.sh

sumitdevbharadwaj · 11-07-2008, 01:15 PM

Hi All,

This is related to shell scripting, if anybody can help me.

I have a situation in which there is a file 'abc' :
#cat abc
students=1000
classes=20
teachers=50

Now I want to write a script in which I call file abc and update 'classes' to 30. so that new file looks like:
#cat abc
students=1000
classes=30 # done bold to clarify.
teachers=50

How can I do this? Can anybody please let me know?

Lots of thanks.

druuna · 11-07-2008, 02:39 PM

Hi,

Sed, amongst others, can do this:

sed -ibak 's/classes=20/classes=30/' infile

The -ibak creates a backup (infile.bak in this case) of the original file before changing it.

I'm not sure if this is homework, so it's up to you to find out what is going on and 'script' it ;-)

Hope this helps.

sumitdevbharadwaj · 11-07-2008, 04:21 PM

Thanks a lot...it works.

sumitdevbharadwaj · 11-07-2008, 04:32 PM

And suppose if there is some attribute rooms whose value I dont know. But whatever it may be I want to set it to 100.
Then what will be the changes in the command???

druuna · 11-07-2008, 04:55 PM

Hi,

Not sure what it is you are asking. Could you give an example (or 2)?

The_Kernel · 11-08-2008, 12:38 AM

Quote:

Originally Posted by sumitdevbharadwaj

And suppose if there is some attribute rooms whose value I dont know. But whatever it may be I want to set it to 100.
Then what will be the changes in the command???

Code:

sed 's/rooms=.*/rooms=100/' -i abc

That's assuming that the "rooms" attribute is the only thing on the line.

sumitdevbharadwaj · 11-09-2008, 01:37 AM

Oh Thanks The Kernel...it is working fine.