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Comparing Text Files

17 Jun 2018

The diff command in Linux will show us the where the lines in text files differ and ignore lines that are the same.

Create Text File 1

echo "Khaydarbi Melikov is a foot soldier." >> regiment_version1.txt
echo "Khaydarbi Melikov is a member of the the Maroon Martyrs regiment" >> regiment_version1.txt

Create Text File 2

echo "Khaydarbi Melikov is a foot soldier." >> regiment_version2.txt
echo "Khaydarbi Melikov is a member of the Reserve regiment" >> regiment_version2.txt

View Text File 1

$ cat regiment_version1.txt

Khaydarbi Melikov is a foot soldier.
Khaydarbi Melikov is a member of the the Maroon Martyrs regiment

View Text File 2

$ cat regiment_version1.txt

Khaydarbi Melikov is a foot soldier.
Khaydarbi Melikov is a member of the Reserve regiment

Create Compare Text Files

diff regiment_version1.txt regiment_version2.txt

2c2
< Khaydarbi Melikov is a member of the the Maroon Martyrs regiment
---
> Khaydarbi Melikov is a member of the Reserve regiment

Notice that the lines that matched are not shown, instead it outputs only the line in both documents that differs.

If we want to see the context around the differences, we can use the -c argument:

diff -c regiment_version1.txt regiment_version2.txt

*** regiment_version1.txt	2018-08-03 11:20:07.313559654 -0700
--- regiment_version2.txt	2018-08-03 11:20:10.077617610 -0700
***************
*** 1,2 ****
  Khaydarbi Melikov is a foot soldier.
! Khaydarbi Melikov is a member of the the Maroon Martyrs regiment
--- 1,2 ----rm
  Khaydarbi Melikov is a foot soldier.
! Khaydarbi Melikov is a member of the Reserve regiment