Unix trivia: echo cat | sed statement
I occasionally run into weird, funny or surprising aspects of Unix and Unix-like Operating Systems. I'll try to post about those regularly because they're fun.
This one popped up on irc a few weeks ago; a google search suggests it's at least 6 months old. I have been unable to track the original source down.
The question is: if you input echo cat | sed statement into your Unix shell, what comes out? Can you predict it? If not, can you try it and then explain it?
'cement' is what comes out, because the 'a' in 'cat' is substituted with 'emen'. Any character other than backslash or newline can be used 't' instead of a slash to delimit the regular expression 'a' and the replacement 'emen'.
Comment by Job — May 24, 2010 11:14:00 AM | # - re
statement has 3 t's, and comes after the s (which is a substitute operator). So the a in cat will be substituted with 'emen', which will yield 'cement' :)
Comment by Emiel — May 24, 2010 11:16:31 AM | # - re