$ cat ejemplo1.txt

John Smith 	1001 	Sr. Engineer
Peter		1002	Engineer
Fernandous	1003	Sr. Engineer
Kraml		1004	Jr. Engineer

$ cat ejemplo2.txt

John Smith 	1001 	Sr. Engineer
Peter		1002	Engineer
Fernandous	1003	Resigned
Kraml		1004	Jr. Engineer
Raj		1005	Engineer

• diff
• colordiff
• wdiff
• dwdiff
• meld

$ diff -u ejemplo1.txt ejemplo2.txt > ejemplo.patch
$ patch < ejemplo.patch 
$ diff -u ejemplo1.txt ejemplo2.txt
$ patch -R < ejemplo.patch
$ diff -u ejemplo1.txt ejemplo2.txt