Linux chmod

Linux chmod

rwx = 111 in binary = 7 (read/write/execute) 
rw- = 110 in binary = 6 (read/write)        
r-x = 101 in binary = 5 (read/execute)
r-- = 100 in binary = 4 (read)
wx- = 011 in binary = 3 (write/execute)
w-- = 010 in binary = 2 (write)
x-- = 001 in binary = 1 (execute)
a = all, o = others, g = group, u = user
r = read, w = write, x = execute, 
X = special execute, s = setuid/gid, t = sticky
chmod u+rw,g-rwx,o-rx <file>