Setting PATHs in .cshrc or .login

[James Board]

I'm a csh user. In my .cshrc or .login files, I'd like to add certain directories to my search PATH, but I'd first like to check if those directories are already in the search path before attempting to add them (so don't add the same directory twice). The following isn't working

if ( "${PATH}" !~ ~/bin ) then
    setenv PATH "${PATH}:$HOME/bin"
endif

The problem is that the if-statements always evaluates to TRUE, meaning that ~/bin is always added to the path, even if it's already in the path.

What am I doing wrong in the above regulat expression, or alternatively, what's an easy way to accomplish the same thing?

[Smoking Tux]

As first, a little typo I guess, '!~' instead of '!='. Secondly, your if-command would only work either $PATH is totally empty or contains nothing but '~/bin'.
Just try:

if ( `echo $PATH | egrep -c '~/bin'` == 0 ) then
    setenv PATH "${PATH}:$HOME/bin"
endif

[James Board]

Thanks. That works. Is there no way to do that in the csh, without running an external shell command?

[Smoking Tux]

I must admit that I'm not very familiar with csh. However, I think there is a way. The problem is, as far as I know, that csh isn't able to read from a pipe, so you have to write some lines more to 'ship around'. Just try following:

set my_paths=/tmp/my_paths
echo $PATH > $my_paths

if  ( { grep -c '~/bin' $my_paths } == 0 ) then
        setenv PATH "${PATH}:$HOME/bin"
endif