So while setting up postfix I came across the following command
chmod o= /etc/postfix/mysql-virtual_*.cf
And I realised I’d not come across the equals (=) operator in the chmod command before. So here’s a quick run down of what it’s used for.
The command format is as follows:
chmod u=rwx,g=rwx,o=rwx [file]
Either of the equals groups is optional e.g. if you just want to set the permissions for the file’s ‘group’:
chmod g=rwx [file]
And you don’t have to provide all of the permssions e.g. if you only want to give the file’s ‘user’ (owner) read permissions:
chmod u=r [file]
To remove the permissions from an entity either leave it blank or add three dashes:
chmod u=--- [file]
or
chmod u= [file]
You can also enter partial permission:
chmod o=rx [file]
Saves having to remember the octal syntax each time (still, it’s good to learn that too!)
A rail in the sky 