chmod 644

Set file permissions numerically

chmod changes file permissions. Numbers represent rwx: 4=read, 2=write, 1=execute. 644 = owner:rw-, group:r--, others:r-- (typical config file). 755 = typical script. 600 = owner:rw-- only (private key).

Example

$ chmod 644 app.conf
$ ls -l app.conf
-rw-r--r-- 1 ubuntu ubuntu 1024 Jan 15 app.conf

Tip: Type it yourself in the terminal below - reading is not the same as doing.