How do I tell inside .cshrc if I’m a login shell?
When people ask this, they usually mean either How can I tell if it’s an interactive shell? or How can I tell if it’s a top-level shell?

You could perhaps determine if your shell truly is a login shell (i.e. is going to
source “.login” after it is done with “.cshrc”) by fooling around with “ps” and
“$$”. Login shells generally have names that begin with a ‘-’. If you’re really
interested in the other two questions, here’s one way you can organize your
.cshrc to find out.

           if (! $?CSHLEVEL) then #
                     # This is a “top-level” shell, # perhaps a login shell, perhaps a shell started up by # ‘rsh machine some-command’
                     # This is where we should set PATH and anything else we
                     # want to apply to every one of our shells.
                     #
                       setenv CSHLEVEL 0
                       set home = ~username # just to be sure source
                                       ~/.env # environment stuff we always want else #
                    # This shell is a child of one of our other shells so 
                    # we don’t need to set all the environment variables again.
                    #
                       set tmp = $CSHLEVEL
                   @ tmp++
                       setenv CSHLEVEL $tmp endif # Exit from .cshrc if not
                        interactive, e.g. under rsh if (! $?prompt) exit # Here we could set the prompt or
                        aliases that would be useful # for interactive shells only.
                         source ~/.aliases How do I construct a shell glob-pattern that matches
                         all files except “.” and “..” ?

You’d think this would be easy.
* Matches all files that don’t begin with a “.”; .
* Matches all files that do begin with a “.”, but this includes the special entries “.” and “..”, which often you don’t want; .[!.]* (Newer shells only; some shells use a “^” instead of the “!”; POSIX shells must accept the “!”, but may accept a “^” as well; all portable applications shall not use an unquoted “^” immediately following the “[“) Matches all files that begin with a “.” and are followed by a non-”.”; unfortunately this will miss “..foo”; .??* Matches files that begin with a “.” and which are at least 3 characters long. This neatly avoids “.” and “..”, but also misses “.a” .

So to match all files except “.” and “..” safely you have to use 3 patterns (if you don’t have filenames like “.a” you can leave out the first): .[!.]* .??* *

Alternatively you could employ an external program or two and use backquote substitution. This is pretty good: `ls -a | sed -e ‘^\.$d’ -e ‘^\.\.$d’` (or `ls -A` in some Unix versions) but even it will mess up on files with newlines, IFS characters or wildcards in their names.

Relevance Read:

• How does a kill Process Work

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