Thread: shell script comparison for two file(text) character wise

diff?
cmp?

Both will more or less give you the information.

But you might have to post-process the results with something else to get the desired format.

Originally Posted by vaibhavs17

Actual problem: I need to write a shell script which can give me difference character by character not by line (using comm)

Personally, I would rather eat glass than use bash for this but here is a starting point:

Code:

#!/bin/bash

i=0
while read line; do
	file[$i]=$line;
	i=$((i+1));
done < "test.sh"

i=0
while [ $i -lt ${#file[*]} ]; do
	j=0
	while [ $j -lt ${#file[$i]} ]; do
		echo ${file[i]:$j:1};
		j=$((j+1));
	done;
	i=$((i+1));
done;

Doesn't that look like fun? This stores "test.sh" in an array of lines, then prints each line one character at a time, like:


#
!
/
b
i
n
/
b
a
s
h


You cannot have multi-dimensional arrays in bash, but if an array element is a string you can deal with the individual characters in a string. For more on arrays:

Arrays

Remember: bash is whitespace sensitive!!!! Also, if you run this script on itself notice what happens with the asterisk on line 10 -- demonstrating shell scripts can be dangerous in unpredictable ways (this one isn't dangerous).