Ubuntu

Hi All,
I m trying to write a small utilities to help me.
I need to create a shell script to which if I give two filenames it will create a some.diff file from that.

I know its very simple, but I am stuck
here is code I have written.

Code:

  1 #this is is diff file generator
  2 
  3 echo $1 $2  
  4 #echo $#
  5 echo script $0 is running in `pwd` directory diff file will be generated in     current directory.
  6 
  7 echo first file enter as $1
  8 echo second file entered as $2
  9 #echo $filename
 10 DIFF_FILENAME=`echo $filename | awk -F"."'{print $1}'`
 11 echo $DIFF_FILENAME
 12 #read DIFF_FILE_NAME 
 13 #diff $1 $2 >

in the line number 10, I am just trying to get diff file name from first file name.
let say have filename1.c, I want the name of diff file as filename1.diff
some how I am not able to cut the name before dot (.) and append the .diff to it.
Anyone please help me out, where I m making mistake.
Thanks in advnace.

~reverser

It's helpful, when you post problems, to say what it is doing, not just what you want it to do. I had to type out the code myself to see what was going wrong...

When I try your code awk prints an error message and usage instructions. Looks like you forgot a space between " and ', when I add it awk does as expected.

Depending on your shell there may be much more efficient ways to do this, like:

Code:

IFS="." read file ext <<< "${filename}"

If you're calling awk, cut, sed, perl, etc. to process single lines of text, that's probably not the best way to do it. awk is an entire complex language by itself, and any of these can process more than one line, so it's overkill and slows your script way down.

Code you have published that worked too well
even that solved the extension problem by itself

but that awk thing is not working I put that space in between, but still that DIFF_FILENAME is Empty string.

any guess about that .

Hi.

I'm missing the bit where you set filename...

Code:

DIFF_FILENAME=`echo $filename | awk -F"."'{print $1}'`

You have to assign the first parameter to the the variable filename before using it:

Code:

filename=$1
DIFF_FILENAME=${filename%.*}.diff