karish@mindcrf.UUCP (Chuck Karish) (09/11/90)
[ This thread belongs in comp.unix.shells. I've directed followups there. --crk ] In article <9434@uudell.dell.com> rjd@ninja.dell.com writes: >In article <1990Sep7.152354.9439@ecn.purdue.edu> patkar@helium.ecn.purdue.edu (The Silent Dodo) writes: >|I have a question about shell scripts. How can a shell script >|(sh or csh) find out its own file name? Actually, I need to >|know only the directory in which it resides. > > Hmmmmm..... Off the top of my head, how about this?: > >COMMAND=`basename $0` >DIR=`type $COMMAND | sed -e 's:^.* /:/:' -e "s:/$COMMAND$::"` >echo "Parent directory of \"$COMMAND\" is \"$DIR\"" Does this work if the script is somewhere in the search path, and $0 is not a path? When I have to do this, I consider three cases: - $0 contains an absolute path. - $0 contains a relative path. - $0 contains a command name that's not a path. If $0 starts with a / (absolute path name), just clip off the file name: CMD=$0 DIR=`echo $CMD | sed 's:/[^/]*$::'` If $0 contains a / but does not start with one (relative path name), do CMD=`pwd`/$0 before using sed as above. If $0 contains a command that your login shell found by searching its $PATH or $path, repeat that logic (or use `which`, if all your systems use it): see whether there's a file you can execute in any of the directories in $PATH, by searching them in order and using test -x. Then clip off the file name with sed. If the shell script has mucked with $0 (can shells do this? C programs sure can) you're hosed: in general, you can't get there from here. Depending on your specific needs, you may or may not wish to add code to eliminate './' and '../' from the paths. If anyone knows a way to do this that's simpler and still maximally portable (to UNIX systems) I'd like to hear about it. Ditto for anything I've left out. -- Chuck Karish karish@mindcraft.com Mindcraft, Inc. (415) 323-9000