How to use permissions

Here is how the chmod command works : 1 = executable 2 = writeable
4 = readable

therefore 1+2+4 = 7 = rwx (from above)
2+4 = 6 = rw
4+1 = 5 = r-x and so on.

lager 2:05pm {0}[~/helpun] chmod 100 *

lager 2:06pm {0}[~/helpun] ls -l

total 2
---x------ 1 cb users 6 Jan 5 14:04 anotherprogramname*
---x------ 1 cb users 3 Jan 5 14:04 programname*

lager 2:06pm {0}[~/helpun] chmod 200 *


lager 2:06pm {0}[~/helpun] ls -l
total 2
--w------- 1 cb users 6 Jan 5 14:04 anotherprogramname
--w------- 1 cb users 3 Jan 5 14:04 programname

lager 2:06pm {0}[~/helpun] chmod 400 *

lager 2:06pm {0}[~/helpun] ls -l
total 2
-r-------- 1 cb users 6 Jan 5 14:04 anotherprogramname
-r-------- 1 cb users 3 Jan 5 14:04 programname

lager 2:06pm {0}[~/helpun]



Now the first digit is for you, the second is for your group(cb is of group users) and the third is other. There are other ways of using this command but I feel using numbers is the easiest.