diff file1.txt file2.txt
but what if I wanted to diff one file with output generated from a different program instead of a file. Well I could send the the output of the program to a file and then diff the two files but there is a much more efficient way.
./program | diff file1.txt -
This will diff the output of program with file1.txt
Now what if I don't have any files but just want to diff outputs of two files?
The solution is redirection:
diff <(./command1) <(./command2)
much nicer than creating intermediate files