using diff command, and ed command to reconstruct text 1

[Guest_imported]

I have a problem, I need to be able to extract the difference between two text files using the diff command and store them in a file on disk. I also need the ability to reconstruct the file using the original(first) file and the differences. I have looked at the Unix command diff and ed however I'm completely confused about how to use them! Any help for a Unix beginner? Cheers Iain

 

[KenCunningham]

In it's simplest form, you can write the differences to a file using the following syntax:

diff file1 file2 > output_file

This will produce an output file containing:

1,5c1,5
< 1
< 2
< 3
< 4
< 5
---
> 6
> 7
> 8
> 9
> 10

for example.

I'm not sure what you are trying to do with ed, but if I get the chance I'll have a think about it.

 

[aigles]

Suppose multiple versions of a file :
File.0 Original file
File.1 Version 1
File.2 Version 2

Create ed scripts :
diff -e File.0 File.1 > File_0_1.ed ; Create ed script File.0 to File.1
diff -e File.1 File.2 > File_1_2.ed ; Create ed script File.1 to File.2


Create a script shell : reconstruct.sh
(shift; cat $*; echo '1,$p') | ed - $1

If you want to reconstruct the latest version of file from original file ad ed scripts :
resconstruct.sh File.0 File_0_1.ed File_1_2.ed > File.last ; = File.2

 

[toolkit]

Aigles, have a star

Iain, it sounds like you may want to look into RCS (

http://www.gnu.org/software/rcs/rcs.html)

or CVS (

http://www.gnu.org/software/cvs/cvs.html)

to consider using some form of file revision control system...

Cheers, Neil