At least once a week, I find myself wishing I could sort two files and compare them in one shot, from the commandline, without creating intermediate files. Today I’m glad to say I found my answer.
Here are two examples:
diff -y <(sort file1) <(sort file2)
comm -3 <(sort file1) <(sort file2)
See this wikipedia entry for a comparison of the diff and comm commands.
