Sharing Files

In the following commands are shown for giving members of a Unix group read permission to files in a sub-directory of an existing base directory.

Never give write permissions to any other user, not even to members of your working group!

Names used in commands

• $WORK is an existing base directory
  • e.g. WORK=/work/username
• groupname is the name of an existing Unix group
  • on Hummel all members of a working group are members of a corresponding Unix group hpc_ag_group
  • the exact name of the Unix group can be found in the output of the id command
• groupdata is the name of a directory to be shared

Commands for a new directory

mkdir $WORK/groupdata
chgrp groupname $WORK
chgrp groupname $WORK/groupdata
chmod g+x $WORK
chmod g+rxs $WORK/groupdata

Commands for an existing directory

chgrp groupname $WORK
chgrp -R groupname $WORK/groupdata
chmod g+x $WORK
chmod -R g+rX $WORK/groupdata
find $WORK/groupdata -type d -exec chmod g+s {} \;

Explanations of commands

Links to Wikipedia:

• mkdir
• chgrp
• chmod
• find