To contrast two files:
sdiff -w 80 email addresses Mike erpl08@ed | John erpl08@ed Joe CZT@cern.ch Joe CZT@cern.ch > Jean JRS@pollux.ucs.co > Jim jim@frolix8 Kim firstname.lastname@example.org Kim email@example.com Sam s.wally@aston < Keith keith@festival Keith keith@festival
This contrasts the two files email on the left and addresses on the right.
The option -w 80 is used to set the width of the output from the command to 80 characters - the most that will fit across most computer terminals. The default is 130 characters.
The first line in each file is different and is marked with a |. Lines 3 and 4 of the file addresses are unique as is line 4 of the file email. All the other lines are identical.