CODEWITHSUNDEEP
tcsh
user1195893
user1195893

Reputation:

If-then-else syntax in tcsh

I'm trying to write a simple script in tcsh (version 6.12.00 (Astron) 2002-07-23), but I am getting tripped up by the if-then-else syntax. I am very new to script writing.

This script works:

#!/bin/tcsh -f
if (1) echo "I disagree"

However, this one does not:

#!/bin/tcsh -f
if ( 1 ) then
  echo "I disagree"
else
  echo "I agree"
endif

For one thing, this code, when run, echoes both statements. It seems to me it should never see the else. For another, the output also intersperses those echoes with three iterations of ": Command not found."

Edited to add: here is the verbatim output:

: Command not found.
I disagree
: Command not found.
I agree
: Command not found.

I know that the standard advice is to use another shell instead, but I am not really in a position to do that (new job, new colleagues, everyone else uses tcsh, want my scripts to be portable).

Upvotes: 3

Views: 6352

Answers (1)

Keith Thompson
Keith Thompson

Reputation: 263277

When I copy-and-paste your script and run it on my system, it correctly prints I disagree.

When I change the line endings to Windows-style, I get:

: Command not found.
I disagree
: Command not found.
I agree
: Command not found.

So, your script very likely has Windows-style line endings. Fix the line endings, and it should work. The dos2unix command is one way to do that (man dos2unix first; unlike most UNIX text-processing commands, it replaces its input file.)

The problem is that tcsh doesn't recognize ^M ('\r') as an end-of-line character. It sees the then^M at the end of the line as a single command, and prints an error message then^M: Command not found. The ^M causes the cursor to return to the beginning of the line, and the rest of the message overwrite the then.

Upvotes: 3

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