c shell environment variable error: "Bad : modifier in $"

I am using tcsh and define an environmental variable as follows:

setenv mycomp 

so that when I need to copy files from the remote my.computer.com, I type the following:

scp $mycomp:sourcepath destpath

But when I do this, I get the following error: "Bad : modifier in $ (m)." where (m) is the first character after the colon.

What is this error telling me, and how can I fix it?

2 Answers

Variable expansion with a colon after it treats the letters after the colon as modifiers.

For example, $dir:h means expand $dir with the h modifier. h means head, i.e. all but the last part of the path.

% set dir=/home/user
% echo $dir:h
/home

All the info is in the tcsh(1) man page:

History substitution ... The word or words in a history reference can be edited, or ‘‘modi- fied’’, by following it with one or more modifiers, each preceded by a ‘:’: h Remove a trailing pathname component, leaving the head. t Remove all leading pathname components, leaving the tail. r Remove a filename extension ‘.xxx’, leaving the root name. e Remove all but the extension. u Uppercase the first lowercase letter. l Lowercase the first uppercase letter. s/l/r/ Substitute l for r. ...
Variable substitution ... The ‘:’ modifiers described under History substitution, except for ‘:p’, can be applied to the substitutions above.

You can avoid the modifier by wrapping the variable name in braces, e.g.

scp ${mycomp}:sourcepath destpath

While I don't have a tcsh environment to test this out I'd guess that when the shell is looking for your environment variable, it is not splitting out on the : and looking for $mycomp:sourcepath as the whole variable name.

I would try aliasing out your scp command.