Set default permisson for newly folders and files in Linux

The use of chmod is for changing permissions, the command chown is for changing ownership of files & directories.

ownership

To change a directory's ownership you can use the following command:

$ sudo chown -R me /srv/www/htdocs 

NOTE: we're using the sudo facility to elevate our privileges to the same level as root for these commands, without having to become root.

permissions

To change the permissions on this directory:

$ sudo chmod -R 777 /srv/www/htdocs 

umask

Using the command umask sets up your terminal so that when files & directories are created their permissions can be influenced a bit. Caution should be used when using umask since there are situations where it won't give you permissions exactly the way you think.

For a directory it seems fine:

$ for i in `seq 1 7`;do echo "umask: 00$i"; umask 00$i; rm -fr blah; mkdir blah;ls -l|grep blah;done umask: 001 drwxrwxrw- 2 saml saml 4096 Jul 29 14:39 blah umask: 002 drwxrwxr-x 2 saml saml 4096 Jul 29 14:39 blah umask: 003 drwxrwxr-- 2 saml saml 4096 Jul 29 14:39 blah umask: 004 drwxrwx-wx 2 saml saml 4096 Jul 29 14:39 blah umask: 005 drwxrwx-w- 2 saml saml 4096 Jul 29 14:39 blah umask: 006 drwxrwx--x 2 saml saml 4096 Jul 29 14:39 blah umask: 007 drwxrwx--- 2 saml saml 4096 Jul 29 14:39 blah 

However it won't let you have files exactly the way you might intend them to be with particular umasks. See umask 006 for example below:

$ for i in `seq 1 7`;do echo "umask: 00$i"; umask 00$i; rm -fr blah; touch blah;ls -l|grep blah;done umask: 001 -rw-rw-rw- 1 saml saml 0 Jul 29 14:40 blah umask: 002 -rw-rw-r-- 1 saml saml 0 Jul 29 14:40 blah umask: 003 -rw-rw-r-- 1 saml saml 0 Jul 29 14:40 blah umask: 004 -rw-rw--w- 1 saml saml 0 Jul 29 14:40 blah umask: 005 -rw-rw--w- 1 saml saml 0 Jul 29 14:40 blah umask: 006 -rw-rw---- 1 saml saml 0 Jul 29 14:40 blah umask: 007 -rw-rw---- 1 saml saml 0 Jul 29 14:40 blah 

There are others, this is just to highlight an example!

So what should you do?

Given you're dealing with a Apache directory (based on the path /srv/www/htdocs) I'd look for a Unix group that your user me and the user that Apache is running as are both members of. You can use the groups command to determine this:

$ groups saml saml : saml vboxusers jupiter newgrp $ groups apache apache : apache 

You can also use the id command:

$ id saml uid=500(saml) gid=501(saml) groups=501(saml),502(vboxusers),503(jupiter),10000(newgrp) $ id apache uid=48(apache) gid=48(apache) groups=48(apache) 

On my system Apache is run by a user apache. Looking at this user you can see that it's in a single group apache as well. So one approach would be to add the user me to this group.

For example, add me to the apache groups:

$ sudo usermod -a -G apache me 

The other approach would be to create another group and add both apache and me to this secondary group (for example, apacheplus), and then run this command on /srv/www/htdocs:

$ sudo chgrp -R apacheplus /srv/www/htdocs