the 10
drwxr-xr-x
the first bit:
| - | regular file |
| b | block special file |
| c | character special file |
| s | socket |
| d | directory |
| l | link |
| p | pipe |
the other nine bits
User --- Group --- Others
chmod [parameter] [mode] [file]
// add execute right to user
chmod u+x a.file //u means user, g means group, o means other , + means add, - means minus, = means assign
// add write right to group and others
chmod g+w, o+w a.file
//delete the execute right from user, delete write right from group and others
chmod u-x, g-w, o-w a.file
use the digit in chmod
4 means r 2 means w 1 means x Ok, this is really important
chmod 744 a.file // rwxr--r--
chmod 755 a.file //rwxr-xr-x
// DON‘T USE 777, That‘s really silly.