Whenever you need to find the differences between two files you should use diff

Diff will output the parts of the files where they are different. Usage

diff [options] file1 file2 diff [options] file1 directory diff [options] directory file2 diff [options] directory1 directory2

file1 and file2 are the files to be compared, but when you use a directory and a file you diff will find a file in directory which file is the same as the compared file, when two directories are used diff will look in both directories for files with the same names to be compared.

Options

   -i  --ignore-case
          Ignore case differences in file contents.

   --ignore-file-name-case
          Ignore case when comparing file names.

   --no-ignore-file-name-case
          Consider case when comparing file names.

   -E  --ignore-tab-expansion
          Ignore changes due to tab expansion.

   -b  --ignore-space-change
          Ignore changes in the amount of white space.

   -w  --ignore-all-space
          Ignore all white space.

   -B  --ignore-blank-lines
          Ignore changes whose lines are all blank.

   -I RE  --ignore-matching-lines=RE
          Ignore changes whose lines all match RE.

   --strip-trailing-cr
          Strip trailing carriage return on input.

   -a  --text
          Treat all files as text.

   -c  -C NUM  --context[=NUM]
          Output NUM (default 3) lines of copied context.

   -u  -U NUM  --unified[=NUM]
          Output NUM (default 3) lines of unified context.

   --label LABEL
          Use LABEL instead of file name.

   -p  --show-c-function
          Show which C function each change is in.

   -F RE  --show-function-line=RE
          Show the most recent line matching RE.

   -q  --brief
          Output only whether files differ.
   -e  --ed
          Output an ed script.

   --normal
          Output a normal diff.

   -n  --rcs
          Output an RCS format diff.

   -y  --side-by-side
          Output in two columns.

   -W NUM  --width=NUM
          Output at most NUM (default 130) print columns.

   --left-column
          Output only the left column of common lines.

   --suppress-common-lines
          Do not output common lines.

   -r  --recursive
          Recursively compare any subdirectories found.

A good one option is the -y –side-by-side as it will display the differences in two columns you can also use the command sdiff to reproduce the -y parameter.