making the changes permanent in a file - Shell Programming and Scripting

vijaya2006 · #1 (**permalink**) 05-22-2007

Hi Friends.
I have a file called install.data which has fields like :

XXXXX
ACVCGFFTFY UAHIUH OI
CONNECTION=tape/11/
LOCATAION=08-90-89
SIZE=90

I had to change the values of some of these variables. So i did :
grep "SIZE" instal.data | sed 's/[0-9]*/00/' ...this is working fine on command line but i want to make this change permanent in the file without redirecting it to
other file .I dont want to make the changes in the Vi editor . I need to use some command . Can you help in this ???

Thanks,
Vijayaa

lazytech · #2 (**permalink**) 05-22-2007

My suggestion would be to have your sed command in a script and have it output to a temp file and then have the mv command write the temp file over the original file.

aigles · #3 (**permalink**) 05-22-2007

If perl is available on your system, you can do something like that :

Code:

perl -p -i -e '/SIZE/ and s/[0-0]*/00/'  instal.data

Jean-Pierre.

ennstate · #4 (**permalink**) 05-22-2007

Hi,
This is a sample script incase you need to run on single or multiple files in a directory.

Code:

#!/bin/ksh
for file in *.txt ; do  
  sed  's/SIZE=[0-9][0-9]*/SIZE=00/g' $file > /tmp/${file}.new;   
  mv ${file} ${file}.old #Taking a backup before overwriting
  mv /tmp/${file}.new $file;
done

Thanks
Nagarajan Ganesan.

matrixmadhan · #5 (**permalink**) 05-22-2007

if thats GNU sed, use the -i option

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