||Home||Switchboard||Unix Administration||Red Hat||TCP/IP Networks||Neoliberalism||Toxic Managers|
|(slightly skeptical) Educational society promoting "Back to basics" movement against IT overcomplexity and bastardization of classic Unix|
|News||Recommended Links||mount command||Linux filesystems||Loopback filesystem|
|Linux Swap filesystem||Swap file||Filesystem mount options||/etc/fstab/||ext2 attributes||Ext3 filesystem|
|udev||Partition labels||Managing Disks by UUID||Loopback filesystem||Linux Disk Partitioning||Grub|
|The Linux Logical Volume Manager||Linux Logical Volume Snapshots||Linux SCSI subsystem||Admin Horror Stories||Linux Tips||Humor|
While the mount process actually mounts the filesystem on some device (or other resource), it is common to simply say that you "mount the device," which is understood to mean "mount the filesystem on the device."
Mounting and unmounting filesystems usually requires root authority. The basic
form of the
mount command takes two parameters: the device (or other
resource) containing the filesystem to be mounted, and the mount point. For example,
to mount partition /dev/sda9 at the mount point /backup you can use the following
# mount /dev/sda9 /backup
The mount point must exist before you mount anything over it. If it does not, you will get an error and need to create the mount point or use a different mount point
When you mount a filesystem over an existing directory, the files on the filesystem you are mounting become the files and subdirectories of the mount point. If the mount point directory already contained files or subdirectories, they are not lost, but are no longer visible until the mounted filesystem is unmounted, at which point they become visible again. It is a good idea to avoid this problem by using only empty directories as mount points.
After mounting a filesystem, any files or directories created or copied to the mount point or any directory below it will be created on the mounted filesystem. So a file such as /dos/sampdir/file.txt will be created on the FAT32 filesystem that we mounted at /dos in our example.
mount command will automatically detect the type of
filesystem being mounted. Occasionally you may need to specify the filesystem type
explicitly using the
-t option as shown
# mount -t vfat /dev/sda9 /dos
To see what filesystems are mounted, use the
mount command with
no parameters. Listing 4 shows our example system. Note that you do not need root
authority to simply list mounted filesystems.
$ mount /dev/sda6 on / type ext4 (rw) proc on /proc type proc (rw) sysfs on /sys type sysfs (rw) devpts on /dev/pts type devpts (rw,gid=5,mode=620) tmpfs on /dev/shm type tmpfs (rw,rootcontext="system_u:object_r:tmpfs_t:s0") /dev/sda2 on /grubfile type ext3 (rw) none on /proc/sys/fs/binfmt_misc type binfmt_misc (rw) sunrpc on /var/lib/nfs/rpc_pipefs type rpc_pipefs (rw) gvfs-fuse-daemon on /home/ian/.gvfs type fuse.gvfs-fuse-daemon (rw,nosuid,nodev,user=ian) dw.raleigh.ibm.com:/vol/vol1/dwcontent on /mnt/dwcontent type nfs (rw,addr=220.127.116.11) /dev/sdb9 on /mnt/sdb9 type ext3 (rw) /dev/sda9 on /dos type vfat (rw) /dev/sr0 on /media/KNOPPIX type iso9660 (ro,nosuid,nodev,uhelper=udisks,uid=1000,gid=1000 ,iocharset=utf8,mode=0400,dmode=0500)
You can also view similar information by displaying /proc/mounts or /etc/mtab, both of which contain information about mounted filesystems.
mount command has several options that override the default
behavior. For example, you can mount a filesystem read-only by specifying
-o ro. If the filesystem is already mounted, add
# mount -o remount,ro /backup
ro, with commas.
Remount commands will not complete successfully if any process has open files or directories in the filesystem being remounted.
In UNIX and early Linux systems, the /dev directory usually contained entries
for all the devices that might ever be attached to a system. Any device that was
used was always located in the same place in the /dev tree, so using names such
as /dev/sda6 was natural. With the advent of hot-plugging of devices such as USB
or Firewire (IEEE 1394) attached devices, a given device might appear in one USB
port today, and that same device might be plugged into a different USB port tomorrow.
In this environment, you might want to always mount your USB stick at /media/myusbstick,
regardless of which USB port you plug it in to. In the article for topic 102, "Learn
Linux, 101: Boot managers," you learned about using labels and UUIDs (Universally
Unique IDs) instead of device names to identify partitions. If the filesystem on
the partition supports either, you can use these with the
too. Use the
blkid command to find out the UUID and label (if present)
associated with a device. Listing 6 shows how to use
blkid to find
the label and UUID for our root partition and then how to create two additional
mount points and mount the root partition at these two additional points. This example
is for illustration. You would not normally do this in a production environment.
# blkid /dev/sda6 /dev/sda6: LABEL="Fedora-13-x86_64" UUID="082fb0d5-a5db-41d1-ae04-6e9af3ba15f7" TYPE="ext4" # mkdir /mnt/sda6label # mkdir /mnt/sda6uuid # mount LABEL="Fedora-13-x86_64" /mnt/sda6label # mount UUID="082fb0d5-a5db-41d1-ae04-6e9af3ba15f7" /mnt/sda6uui
With the advent of udev, you will usually find additional symbolic links in the /dev directory for devices such as hard drives.
$ find /dev -lname "*sda6" /dev/disk/by-label/Fedora-13-x86_64 /dev/disk/by-uuid/082fb0d5-a5db-41d1-ae04-6e9af3ba15f7 /dev/disk/by-path/pci-0000:00:1f.2-scsi-0:0:0:0-part6 /dev/disk/by-id/wwn-0x50014ee001a8d027-part6 /dev/disk/by-id/scsi-SATA_WDC_WD1001FALS-_WD-WMATV3772868-part6 /dev/disk/by-id/ata-WDC_WD1001FALS-00J7B1_WD-WMATV3772868-part6 /dev/block/8:6
You can also use a symbolic link as another way of specifying the device name when mounting a device.
Once /boot filesystem is mounted, the initialization process runs
-a option to automatically mount a set of filesystems. The
set is specified in the file /etc/fstab.
UUID=082fb0d5-a5db-41d1-ae04-6e9af3ba15f7 / ext4 defaults 1 1 UUID=488edd62-6614-4127-812d-cbf58eca85e9 /grubfile ext3 defaults 1 2 UUID=2d4f10a6-be57-4e1d-92ef-424355bd4b39 swap swap defaults 0 0 UUID=ba38c08d-a9e7-46b2-8890-0acda004c510 swap swap defaults 0 0 tmpfs /dev/shm tmpfs defaults 0 0 devpts /dev/pts devpts gid=5,mode=620 0 0 sysfs /sys sysfs defaults 0 0 proc /proc proc defaults 0 0
# /etc/fstab: static file system information. # # Use 'blkid -o value -s UUID' to print the universally unique identifier # for a device; this may be used with UUID= as a more robust way to name # devices that works even if disks are added and removed. See fstab(5). # # <file system> <mount point> <type> <options> <dump> <pass> proc /proc proc defaults 0 0 # / was on /dev/sda7 during installation UUID=8954fa66-e11f-42dc-91f0-b4aa480fa103 / ext3 errors=remount-ro 0 1 # /grubfile was on /dev/sda2 during installation UUID=3a965842-b6dd-4d52-8830-2d0fdb4284a2 /grubfile ext3 defaults 0 2 /dev/sda5 none swap sw 0 0 /dev/scd0 /media/cdrom0 udf,iso9660 user,noauto,exec,utf8 0 0 /dev/fd0 /media/floppy0 auto rw,user,noauto,exec,utf8 0 0
Lines starting with a # character are comments. Remaining lines contain six fields. Because the fields are positional, they must all be specified.
mountto automatically determine the type, specify
autoas is done in the last line of Listing 9 for the floppy drive.
defaultsif you want default mount options. Some options you will want to know about are:
rospecify whether the filesystem should be mounted read-write or read-only.
noautospecifies that this filesystem should not be automatically mounted at boot time or whenever
mount -ais issued. In our example, this is done for the removable drives.
userspecifies that a non-root user is permitted to mount and unmount the filesystem. This is especially useful for removable media. In older systems, this option is specified in /etc/fstab rather than on the
mountcommand. With newer systems, it may be specified in udev rules that are located in rules files within /lib/udev/rules.d or /etc/udev/rules.d. The options for the DVD drive on my Fedora 13 system come from udev rules, and that is why there is no entry in /etc/fstab for an optical drive.
noexecspecify whether or not to allow execution of files from the mounted filesystem. User-mounted filesystems default to
execis specified after
noatimewill disable recording of access times. Not using access times may improve performance.
dumpcommand should consider this ext2 or ext3 filesystem for backups. A value of 0 tells
dumpto ignore this filesystem.
When you mount a filesystems that is listed in /etc/fstab, you can give either the device name or the mount point when mounting the filesystem. You do not need to give both.
On some systems, for example SUSE 11.2, you may find that the
generated at install time uses symbolic links to the device. So, you may see /dev/disk/by-id/ata-WDC_WD1001FALS-00J7B1_WD-WMATV3772868-part6,
rather than /dev/sda6 for the file system value.
Consult the man pages for
for additional information, including options not covered here.
All mounted filesystems are usually unmounted automatically by the system when it is rebooted or shut down. When a filesystem is unmounted, any cached filesystem data in memory is flushed to the disk.
You may also unmount filesystems manually. Indeed, you should do this when removing writable media such as diskettes or USB drives or memory keys.
umount command to unmount the filesystem, specifying
either the device name or mount point as an argument. Listing 10 shows how to
unmount /dos, then remount it and unmount again using the device name.
# umount /dos # mount /dev/sda9 /dos # umount /dev/sda9
After a filesystem is unmounted, any files in the directory used for the mount point are visible again.
If you attempt to unmount a filesystem while a process has open files on that
filesystem, you will see an error message. Before unmounting a filesystem, you should
check that there are no processes running that have open files on the filesystem.
fuser command to determine what files
are open or what process has open files. You may need the
lsof to avoid warning messages related to the Gnome Virtual File
system (gvfs). Check the man pages to learn about additional mount options and
lsof. If you are checking a whole device, you can specify the device
name or the mount point. You may also check whether an individual file is in use
To illustrate these commands, I created a copy of /etc/fstab on /dos and a small
script to read lines from stdin and print them to stdout with a 10 second pause
between each line. Listing 11 shows the error message from
files are in use and the use of
fuser to check
for open files on /dos, or the underlying device /dev/sda9.
root@echidna ~]# umount /dos umount: /dos: device is busy. (In some cases useful info about processes that use the device is found by lsof(8) or fuser(1)) # lsof -w /dos COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME slowread. 2560 ian 0r REG 8,9 899 123 /dos/fstab sleep 2580 ian 0r REG 8,9 899 123 /dos/fstab # lsof -w /dev/sda9 COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME slowread. 2560 ian 0r REG 8,9 899 123 /dos/fstab sleep 2580 ian 0r REG 8,9 899 123 /dos/fstab # fuser -m /dos /dos: 2560 2586 # fuser -m /dev/sda9 /dev/sda9: 2560 2588
At this point you can either wait until the filesystem is no longer busy, or
you can do a lazy unmount, by specifying the
-l option. A lazy
unmount detaches the filesystem from the filesystem tree immediately, and cleans
the references to the filesystem when it is no longer busy.
We mentioned some issues with removable devices such as USB or Firewire (IEEE
1394) attached devices. It is inconvenient to switch to root access every time you
need to mount or unmount such a device. The same goes for CD, DVD, and floppy drives,
where you need to unmount the device to change media. In the discussion of
fstab above, we mentioned the
user option, which allows ordinary
users to mount and unmount devices. Listing 9 shows one way to code
entries for a floppy drive or for a CD or DVD drive.
Note that the filesystem types for the optical drive are specified as
while the filesystem type for the floppy is specified as
the optical drive, the mount process will check first for a udf filesystem (common
on DVD) and then for an iso9660 filesystem (common on CD). For the floppy drive,
the mount process will probe for a filesystem type. You can create or edit /etc/filesystems
to change the order in which the filesystems will be probed.
Note: You should always unmount removable drives or media before disconnecting the drive or attempting to remove the media. Failure to do so may result in loss of data that has not yet been written to the device.
If you run a graphical desktop such as Nautilus, you will usually find options
that allow removable devices and media to be automatically mounted. For example,
if I insert a Knoppix DVD into the DVD drive of my system, I might see a mount entry
such as shown in Listing 12. The presence of 'uid=1000' shows that the user with
id 1000 can unmount this disc. The
id command shows the uid for user
ian is 1000, so ian can unmount this disc.
$ mount | grep sr0 /dev/sr0 on /media/KNOPPIX type iso9660 (ro,nosuid,nodev,uhelper=udisks, uid=1000,gid=1000,iocharset=utf8,mode=0400,dmode=0500) $ id ian uid=1000(ian) gid=1000(ian) groups=1000(ian)
You may also use the
eject command to eject removable media when
the drive supports the operation as most CD and DVD drives do. If you have not unmounted
the device first, then
eject will both unmount and eject the disc.
You may have noticed in the discussion of
fstab above that swap
space does not have a mount point. The boot process usually enables swap space defined
in /etc/fstab unless the
noauto option is specified. To manually control
swap space on a running system—for example, if you added a new swap partition—use
swapoff commands. See the man pages for
$ swapon -s Filename Type Size Used Priority /dev/sdb1 partition 514044 0 -1 /dev/sdb5 partition 4192928 0 -2 $ cat /proc/swaps Filename Type Size Used Priority /dev/sdb1 partition 514044 0 -1 /dev/sdb5 partition 4192928 0 -2
fdisk -l is your friend
the device is visible in YAST/system/hardware
Some devices will be supported and some are not. You can check on www.linuxhardware.net to see if device supported.
First plug your usb card reader and to make sure your device was detected go
to System Tools > Hardware Browser
> enter root password and it will display your hardware information then go to >
Hard Drives and it should be listed under /dev/sdc or other device name.
Open your favorite terminal....btw this works in gnome and kde.
$ cd /mnt/ <-as user cd yourself to the mnt folder and become root to
# mkdir usbflash <- this created a directory in the mnt folder
# ls /mnt/ <-this command listed all my directories the mnt folder
cdrom cdrom1 floppy usbflash
# mount /dev/sda1 /mnt/usbflash <-this is the command to mount flash card reader
# ls usbflash <-this listed all the info in my usb flash card and this
was the output:
bootex.log dns.bmp games and keys LinuxDocs01.21.04 pc's
dns2.bmp Documents LinuxDistributions_eBay my pics programs
then i just copied this to my home folder and i was done!
# umount /dev/sda1 /mnt/usbflash <-this unmounted my usb flash card
umount: /dev/sda1: not mounted
THIS ALSO WORKED UNDER Mandrake 9.1, 9.2, and 10 official.
in terminal type as root: gedit /etc/fstab and NOW YOU CAN ADD THIS LINE TO FSTAB to auto mount it:
/dev/sda1 /mnt/usbflash vfat noauto,users,rw,umask=0 0 0
Adding "rw" allows to read and write in the usb flash drive. HAVE FUN!!
Please note that under FC3 it automounts in your desktop. It is plug and play.
Groupthink : Two Party System as Polyarchy : Corruption of Regulators : Bureaucracies : Understanding Micromanagers and Control Freaks : Toxic Managers : Harvard Mafia : Diplomatic Communication : Surviving a Bad Performance Review : Insufficient Retirement Funds as Immanent Problem of Neoliberal Regime : PseudoScience : Who Rules America : Neoliberalism : The Iron Law of Oligarchy : Libertarian Philosophy
War and Peace : Skeptical Finance : John Kenneth Galbraith :Talleyrand : Oscar Wilde : Otto Von Bismarck : Keynes : George Carlin : Skeptics : Propaganda : SE quotes : Language Design and Programming Quotes : Random IT-related quotes : Somerset Maugham : Marcus Aurelius : Kurt Vonnegut : Eric Hoffer : Winston Churchill : Napoleon Bonaparte : Ambrose Bierce : Bernard Shaw : Mark Twain Quotes
Vol 25, No.12 (December, 2013) Rational Fools vs. Efficient Crooks The efficient markets hypothesis : Political Skeptic Bulletin, 2013 : Unemployment Bulletin, 2010 : Vol 23, No.10 (October, 2011) An observation about corporate security departments : Slightly Skeptical Euromaydan Chronicles, June 2014 : Greenspan legacy bulletin, 2008 : Vol 25, No.10 (October, 2013) Cryptolocker Trojan (Win32/Crilock.A) : Vol 25, No.08 (August, 2013) Cloud providers as intelligence collection hubs : Financial Humor Bulletin, 2010 : Inequality Bulletin, 2009 : Financial Humor Bulletin, 2008 : Copyleft Problems Bulletin, 2004 : Financial Humor Bulletin, 2011 : Energy Bulletin, 2010 : Malware Protection Bulletin, 2010 : Vol 26, No.1 (January, 2013) Object-Oriented Cult : Political Skeptic Bulletin, 2011 : Vol 23, No.11 (November, 2011) Softpanorama classification of sysadmin horror stories : Vol 25, No.05 (May, 2013) Corporate bullshit as a communication method : Vol 25, No.06 (June, 2013) A Note on the Relationship of Brooks Law and Conway Law
Fifty glorious years (1950-2000): the triumph of the US computer engineering : Donald Knuth : TAoCP and its Influence of Computer Science : Richard Stallman : Linus Torvalds : Larry Wall : John K. Ousterhout : CTSS : Multix OS Unix History : Unix shell history : VI editor : History of pipes concept : Solaris : MS DOS : Programming Languages History : PL/1 : Simula 67 : C : History of GCC development : Scripting Languages : Perl history : OS History : Mail : DNS : SSH : CPU Instruction Sets : SPARC systems 1987-2006 : Norton Commander : Norton Utilities : Norton Ghost : Frontpage history : Malware Defense History : GNU Screen : OSS early history
The Peter Principle : Parkinson Law : 1984 : The Mythical Man-Month : How to Solve It by George Polya : The Art of Computer Programming : The Elements of Programming Style : The Unix Hater’s Handbook : The Jargon file : The True Believer : Programming Pearls : The Good Soldier Svejk : The Power Elite
Most popular humor pages:
Manifest of the Softpanorama IT Slacker Society : Ten Commandments of the IT Slackers Society : Computer Humor Collection : BSD Logo Story : The Cuckoo's Egg : IT Slang : C++ Humor : ARE YOU A BBS ADDICT? : The Perl Purity Test : Object oriented programmers of all nations : Financial Humor : Financial Humor Bulletin, 2008 : Financial Humor Bulletin, 2010 : The Most Comprehensive Collection of Editor-related Humor : Programming Language Humor : Goldman Sachs related humor : Greenspan humor : C Humor : Scripting Humor : Real Programmers Humor : Web Humor : GPL-related Humor : OFM Humor : Politically Incorrect Humor : IDS Humor : "Linux Sucks" Humor : Russian Musical Humor : Best Russian Programmer Humor : Microsoft plans to buy Catholic Church : Richard Stallman Related Humor : Admin Humor : Perl-related Humor : Linus Torvalds Related humor : PseudoScience Related Humor : Networking Humor : Shell Humor : Financial Humor Bulletin, 2011 : Financial Humor Bulletin, 2012 : Financial Humor Bulletin, 2013 : Java Humor : Software Engineering Humor : Sun Solaris Related Humor : Education Humor : IBM Humor : Assembler-related Humor : VIM Humor : Computer Viruses Humor : Bright tomorrow is rescheduled to a day after tomorrow : Classic Computer Humor
The Last but not Least Technology is dominated by two types of people: those who understand what they do not manage and those who manage what they do not understand ~Archibald Putt. Ph.D
Copyright © 1996-2020 by Softpanorama Society. www.softpanorama.org was initially created as a service to the (now defunct) UN Sustainable Development Networking Programme (SDNP) without any remuneration. This document is an industrial compilation designed and created exclusively for educational use and is distributed under the Softpanorama Content License. Original materials copyright belong to respective owners. Quotes are made for educational purposes only in compliance with the fair use doctrine.
FAIR USE NOTICE This site contains copyrighted material the use of which has not always been specifically authorized by the copyright owner. We are making such material available to advance understanding of computer science, IT technology, economic, scientific, and social issues. We believe this constitutes a 'fair use' of any such copyrighted material as provided by section 107 of the US Copyright Law according to which such material can be distributed without profit exclusively for research and educational purposes.
This is a Spartan WHYFF (We Help You For Free) site written by people for whom English is not a native language. Grammar and spelling errors should be expected. The site contain some broken links as it develops like a living tree...
|You can use PayPal to to buy a cup of coffee for authors of this site|
Last modified: September 29, 2016