file Permissions 1

[ahmedmt1981]

Dears
Could you please tell me what is the difference betweem the below permission

x,s,S,
and what is t permission means

many many thanks in advance

 

[Mike042]

The x indicates a file is executable (or a directory is accessible) by the Owner, Group or 'Others' depending where in the permission string the 'x' is.

The s in the owner permissions execute field indicates the 'setuid' bit has been set (it allows a user process to 'execute' the file as if they were the owner, ie have the owner's (usually root) permissions).

The s in the group permissions execute field indicates the 'setgid' bit has been set (it allows a user process to 'execute' the file as if they were in the group, ie have the group's permissions).

If the s (in owner) is capitalised (ie S), it means that the 'setuid' bit has been set but the ordinary owner permission 'x' has been denied.

If the s (in group) is changed to l (lowercase EL), it means that the 'setgid' bit has been set but the ordinary group permission 'x' has been denied.

The t indicates that the 'sticky bit' has been set (most often seen on /tmp directory) which allows anyone to write files in the directory, but prevents files being deleted by anyone but the owner (and root).

I hope that helps.

Mike

 

[Annihilannic]

Also note that 's' in the owner permissions of a directory means that any new files created in that directory will be owned by owner of that directory, regardless who creates them. Similarly if 's' is set on the group permissions, the group ownership will be inherited.

Annihilannic.