UNIX for Dummies Questions & Answers

I want to try the unix pipe, the command is like this:
echo new | find .

the standard output of the echo should be "new", then I guess find command will use this output as input to find the file named "new". But the output is all the file names in my current dir, the last line is "echo: write error: Broken pipe".

Can anyone kindly tell me why this is happening? Thanks.

find does not read input from a pipe. That's why you got the error.

Code:

find . -name new

assuming that new is real file name you expect to find. There is no "new" predicate for the find command.

How about this

Code:

ls | grep 'a'

This finds all the files with the letter a in the filename in the current directory.

I see. Thanks a lot.
Is there any other command which does not accept input from pipe?

The "df" command is one of many commands which does not accept input from a pipe.

Many thanks~~

echo's another There's a lot, and a comprehensive list would be difficult and not really all that useful.

Since you've discovered the difference, you may find xargs useful, it's a bridge between arguments and pipes:

Code:

echo new | xargs find

find . | xargs echo

...both pretty useless examples, but you get the idea.