hello,

I have a problem in replacing a value with another one in a file,the actual situation is i am writing an shell script,in that i want to cat a file and that replace the values in the file with a calculated values,which is in a variable...

regards
babu

well this can also be done.

#!/bin/ksh
#initialize the variable for e.g the variable is var1
#your calculaions go here. for var=var+1
vi fname <<!
:%s/search_string/$var1/g
:wq
!

You could try using 'sed'...
To replace 'bob' with whatever's in the variable $jim, do:

#/bin/sh
jim=&lt;some-calculation&gt;
cat <filename> | sed "s/bob/$jim/g"

It's a lot nicer...

NB: If $jim contains '/' characters, do this instead:

cat &lt;filename&gt; | sed "s/bob/$(echo $jim | sed 's/\//\\\//g')/g"

... ok... maybe it's not that nice

Remember, double quotes are needed if a variable is to be expanded inside them.