Cshell commands

Question

When I receive lines one by one, why do programmers sometimes write:

set line = ($<)
set line = ($line)

What exactly do those rows mean?

Answer 1

Hi Chan,

I found a csh overview here: http://linux.die.net/man/1/csh

I appreciate you may not use Linux but I always found O'Reilly's Linux in a Nutshell book great for shell scripting.

To specifically address your questions (from the post above so I could be wrong!)

• $< : get next line from stdin
• ($line) : will execute the contents of $line in a subshell

Of course, like all things with Csh - you should probably just use Bash and live happier :)

Dan

Answer 2

set line = ($<)

This reads a line of input from stdin and then splits it into an array, separating words by white-space, so that $line[1] is the first word, $line[2] is the second word and so on.

set line = ($line)

This does the same as above, but where $line might have been a single word, it will become an array of words. i.e.:

set line = ($<)

is the same as:

set line = "$<"
set line = ($line)