UNIX for Dummies Questions & Answers

The behavior of the following 2 operations is unexpected. K1 and K2 are files here :-

1) cat < K1 K2
The above operation should actually display contents of the both files.
But it gives the contents of K2 only. How is that ?

2) cat > K1 K2
Above operation takes the contents of K2 and writes it to K1 similar to
cat K2 > K1. How is that ?

Request anyone to please let me know.

Thanks a lot in advance.

Best Regards,
Marconi.

I'm curious, what makes you think it should do that? My man page states
(my emphasis), which I understand to mean "not both", i.e. if you give cat a file to read from, standard input is ignored.

Code:

cat > K1 K2

Like Latin, the word order is not as important as the syntax. >K1 means that the output goes into K1. You can achieve the same affect with

Code:

>K1 cat K2

It's the expected behaviour: you need to pass to cat multiple filenames as arguments without the shell redirection (as far as I know only Z-Shell with the multios option set can handle multiple arguments with redirection).
The same for output redirection - you can do it with Z-Shell, otherwise you should use the tee command.