I have a file on my HDD,cd /media/celebisait/5AC69788C6976355There is my file called myFile.tar.gz. I do als -l,-rw------- 2 celebisait celebisait  1387745311 Jun  6  2013 myFile.tar.gzEverything seems fine. However, when I do,$ sudo chmod 755 myFile.tar.gzI do not have any errors but nothing happens, i.e., when I do ls -l again, I get the same output,-rw------- 2 celebisait celebisait  1387745311 Jun  6  2013 myFile.tar.gzChmod does not change.. Why?PS: I use Ubuntu 13.04.Edit:$ cd /media/celebisait/5AC69788C6976355$ dfFilesystem     1K-blocks      Used Available Use% Mounted on/dev/sda2       89873576  42976028  42325544  51% /none                   4         0         4   0% /sys/fs/cgroupudev            16436736         4  16436732   1% /devtmpfs            3289260       920   3288340   1% /runnone                5120         0      5120   0% /run/locknone            16446280       764  16445516   1% /run/shmnone              102400        52    102348   1% /run/user/dev/sda1          94759      2208     92551   3% /boot/efi/dev/sdb1      767999996 541212516 226787480  71% /media/celebisait/5AC69788C6976355/dev/sdb2      767999996   1466472 766533524   1% /media/celebisait/54D09DBDD09DA5B0Edit 2:$ cd /media/celebisait/5AC69788C6976355$ mount/dev/sda2 on / type ext4 (rw,errors=remount-ro)proc on /proc type proc (rw,noexec,nosuid,nodev)sysfs on /sys type sysfs (rw,noexec,nosuid,nodev)none on /sys/fs/cgroup type tmpfs (rw)none on /sys/fs/fuse/connections type fusectl (rw)none on /sys/kernel/debug type debugfs (rw)none on /sys/kernel/security type securityfs (rw)none on /sys/firmware/efi/efivars type efivarfs (rw)udev on /dev type devtmpfs (rw,mode=0755)devpts on /dev/pts type devpts (rw,noexec,nosuid,gid=5,mode=0620)tmpfs on /run type tmpfs (rw,noexec,nosuid,size=10%,mode=0755)none on /run/lock type tmpfs (rw,noexec,nosuid,nodev,size=5242880)none on /run/shm type tmpfs (rw,nosuid,nodev)none on /run/user type tmpfs (rw,noexec,nosuid,nodev,size=104857600,mode=0755)/dev/sda1 on /boot/efi type vfat (rw)binfmt_misc on /proc/sys/fs/binfmt_misc type binfmt_misc (rw,noexec,nosuid,nodev)gvfsd-fuse on /run/user/celebisait/gvfs type fuse.gvfsd-fuse (rw,nosuid,nodev,user=celebisait)/dev/sdb1 on /media/celebisait/5AC69788C6976355 type fuseblk (rw,nosuid,nodev,allow_other,default_permissions,blksize=4096)/dev/sdb2 on /media/celebisait/54D09DBDD09DA5B0 type fuseblk (rw,nosuid,nodev,allow_other,default_permissions,blksize=4096)Edit 3:$ sudo fdisk -l /dev/sdb1Disk /dev/sdb1: 786.4 GB, 786432000000 bytes255 heads, 63 sectors/track, 95611 cylinders, total 1536000000 sectorsUnits = sectors of 1 * 512 = 512 bytesSector size (logical/physical): 512 bytes / 4096 bytesI/O size (minimum/optimal): 4096 bytes / 4096 bytesDisk identifier: 0x6e697373This doesn't look like a partition tableProbably you selected the wrong device.     Device Boot      Start         End      Blocks   Id  System/dev/sdb1p1   ?  1936269394  3772285809   918008208   4f  QNX4.x 3rd partPartition 1 does not start on physical sector boundary./dev/sdb1p2   ?  1917848077  2462285169   272218546+  73  UnknownPartition 2 does not start on physical sector boundary./dev/sdb1p3   ?  1818575915  2362751050   272087568   2b  UnknownPartition 3 does not start on physical sector boundary./dev/sdb1p4   ?  2844524554  2844579527       27487   61  SpeedStorPartition 4 does not start on physical sector boundary.Partition table entries are not in disk orderEdit 4:$ sudo fdisk -l /dev/sdbDisk /dev/sdb: 2000.4 GB, 2000398934016 bytes255 heads, 63 sectors/track, 243201 cylinders, total 3907029168 sectorsUnits = sectors of 1 * 512 = 512 bytesSector size (logical/physical): 512 bytes / 4096 bytesI/O size (minimum/optimal): 4096 bytes / 4096 bytesDisk identifier: 0x9c73d093   Device Boot      Start         End      Blocks   Id  System/dev/sdb1            2048  1536002047   768000000    7  HPFS/NTFS/exFAT/dev/sdb2      1536002048  3072002047   768000000    7  HPFS/NTFS/exFAT/dev/sdb3      3072002048  3907026943   417512448    7  HPFS/NTFS/exFAT
Can't apply chmod to a file
ubuntu;chmod
TL;DR;NOTE: Based on the continuous updating of the question by the OP with new information it was determined that the issue was he was mounting a NTFS partition. So #3 below is the actual answer to his problem. I leave the other 2 methods here for others that may encounter similar issues that aren't using an NTFS partition.Idea #1 - media's readonly (ISO/CD/DVD)?Take a look at the output of the mount command, specifically something like this:$ mount | grep '/media'The device that's mounted under /media/celebisait is likely either an ISO file or a CD/DVD media. In which case you won't be able to gain write access to, since these are typically read only.You can tell what's mounted read/write vs. readonly by again turning to the mount command's output.Example/dev/mapper/fedora_greeneggs-root on / type ext4 (rw,relatime,seclabel,data=ordered)Notice the output in the parenthesis. The first argument before the first comma is rw which denotes read/write access. If it were a readonly device it would have a ro there instead.Alternative methodYou can also find out what device a particular location on your HDD is sourced from by using the df -h . command. This will show you the current directory's source device.$ df -h .Filesystem                         Size  Used Avail Use% Mounted on/dev/mapper/fedora_greeneggs-home  402G  156G  226G  41% /homeHere we can see that I'm in a directory/subdirectory that's part of the mount /home, which is backed by the device /dev/mapper/fedora_greeneggs-home.With the device's name you could then look for that as well in the output of mount.Example$ mount | grep '/dev/mapper/fedora_greeneggs-home'/dev/mapper/fedora_greeneggs-home on /home type ext4 (rw,relatime,seclabel,data=ordered)Idea #2 - But the device is mounted read/write!If you find that your device is mounted read/write you might want to try installing PySDM - a Storage Device Manager that allows full customization of hard disk mountpoints without manual access to /etc/fstab. It also allows the creation of udev rules for dynamic configuration of storage devicessteps to read/writeinstall physical storage device manager: sudo apt-get install pysdmopen storage device manger: sudo pysdmchoose your required drivespress assistuncheck open as read onlycheck owner user of file system and write your username: celebisaitpress okpress applyumount Drivemount itSource: How can I change permissions on external drives?Idea #3 - NTFS partitionsBased on the output you posted for the command:$ sudo fdisk -l /dev/sdb...   Device Boot      Start         End      Blocks   Id  System/dev/sdb1            2048  1536002047   768000000    7  HPFS/NTFS/exFATYou have NTFS partitions, which explains why you weren't able to chmod the files on the NTFS mounted partition(s). If you're using the ntfs-3g module to access  the NTFS partition you should be able to read/write the disk, just not affect its permissions using the normal Unix suite of tools.https://wiki.archlinux.org/index.php/NTFS-3G