Question

I have a script where the user should be able to enter a string with spaces. So far I have:

#bin/csh  echo 'TEST 1' echo -n 'Input : ' set TEST = $<  echo 'Var | ' $TEST  set TEST=`echo $TEST`  echo 'Var after echo | ' $TEST  set TEST=`echo $TEST | sed 's/ /_/g'`  echo 'Var after change | ' $TEST 

If I enter the string ‘r r r’ at ‘input’, $TEST would only take ‘r’. I want to be able to set $TEST to ‘r r r’. Is this possible? If I enter a string like ‘1 1 1’ I get an error:

set: Variable name must begin with a letter.

What’s the reason for this?

Answer 1

It’s because you’re not using quotes in your SET statement. When you enter 'r r r' as your input, the two different variants (unquoted and quoted) are equivalent to:

set TEST=$<    :is equivalent to:  set TEST=r r r set TEST='$<'  :is equivalent to:  set TEST='r r r' 

The first of those simply sets TEST to 'r' and r to '' (twice!). The second sets TEST to 'r r r'. That’s because csh lets you do multiple assignments like:

set a=1 b=2 c d=4 

So you need to use the quoted variant of SET. Examine the following transcript to see how it works:

[pax ~]$ set x=$< ; echo .$x. hello .hello.  [pax ~]$ set x='$<' ; echo $x ; echo .$b.$c. a b c .a b c. b: Undefined variable.  [pax ~]$ set x=$< ; echo $x ; echo .$b.$c. a b c .a. ...  [pax ~]$ set x=$< ; echo $x ; echo .$b.$c. a b=7 c=urk! .a. .7.urk!. 

The reason you’re getting the error you describe with input of '1 1 1' is because you’re effectively executing:

set TEST=1 1 1 

and csh is taking this to mean that you want to create the variable TEST set to '1' followed by the variable 1, which doesn’t start with a letter, hence not allowed. With the quoted variant, this becomes:

set TEST='1 1 1' 

which will do what you expect.