How can I check the permissions of a file in Linux?

You can use the `ls -l` command in the terminal. This will display a detailed listing of the file, including its permissions. The permissions are represented by a string of characters like `-rwxr-xr--`. The first character indicates the file type, and the next nine characters represent the permissions for the owner, group, and others, respectively. 'r' means read, 'w' means write, and 'x' means execute.