I think there’s at least a time in human-being’s life when you feel impugned about the time that single small error, but really hard to be traced, wastes, obstructs and then makes you silly. Even an expert cannot deny this fact. In Linux, this could be more idiotic after you find out that the you already knew about how basic and simple the error was made of! Anyone having a basic know-how of Linux filesystem may know that directory permissions supercede file permissions. For instance, you may forgot to check permissions on all preceding directories, specially the root mount point, when it’s getting ‘permissions denied’ error even having all rwx permissions on it. Despite the fact being simply understandable, it took time to find out that the permissions of ‘/’ root directory mount point were the culprits.

$ ssh -vl abbas 10.10.10.251

Last login: Mon Jul  5 03:58:16 2010 from 10.10.10.243
Could not chdir to home directory /home/abbas: Permission denied
/bin/bash: Permission denied
debug1: channel 0: free: client-session, nchannels 1
Connection to 10.10.10.251 closed.
Transferred: sent 2048, received 2072 bytes, in 0.0 seconds
Bytes per second: sent 51120.7, received 51719.8
debug1: Exit status 1

# stat /
File: `/'
Size: 4096          Blocks: 16         IO Block: 4096   directory
Device: fd00h/64768d    Inode: 2           Links: 23
Access: (0700/drwx------)  Uid: (    0/    root)   Gid: (    0/    root)
Access: 2010-07-04 04:02:02.000000000 -0400
Modify: 2010-07-02 10:14:43.000000000 -0400
Change: 2010-07-05 03:58:50.000000000 -0400