Mastering Linux Security and Hardening

Setting permissions with the symbolic method

Whenever you create a file as a normal user, by default, it will have read and write permissions for the user and the group, and read permissions for others. If you create a program file, you have to add the executable permissions yourself. With the symbolic method, you could use one of the following commands to do so:

chmod u+x donnie_script.shchmod g+x donnie_script.shchmod o+x donnie_script.shchmod u+x,g+x donnie_script.shchmod a+x donnie_script.sh

The first three commands add the executable permission for the user, the group, and others. The fourth command adds executable permissions for both the user and the group, and the last command adds executable permissions for everybody (a for all). ...