Ubuntu linux 2

Question 19 Which signal is the default sent to processes by the kill utility? -9 -1 -15 -2

-15 Explanation The default signal sent to processes by kill is -15, which performs as graceful a termination as possible. Use the -1 signal for hangup/disconnects; -2 is used by interrupt sequences (such as Ctrl+C); and -9 terminates the process regardless of any dependencies that may exist.

Question 18 Which dpkg option completely removes a package and its configuration files? -r -R @-P --configure

-P Explanation The dpkg command installs Debian packages on Debian distributions. The dpkg -P completely uninstall the package including the configuration files.

Question 40 You have an application whose group is sys but you want all users, whether or not they are members of the sysadmin group, to execute the application with sysadmin group permissions. Which of the following examples shows correct usage of the SGID flag? -rwxr-sr-- 3 root sysadmin 73748 Nov 22005 /usr/bin/applicationx -rwxr-sr-s 3 root sysadmin 73748 Nov 2 2005 /usr/bin/applicationx -rwxr--r-s 3 root sysadmin 73748 Nov 22005 /usr/bin/applicationx -rwsr--r-- 3 root sysadmin 73748 Nov 2 2005 /usr/bin/applicationx

-rwxr-sr-- 3 root sysadmin 73748 Nov 22005 /usr/bin/applicationx Explanation Placing the s bit in the execute location for the group's permissions, as shown here-rwxr-sr--, means that anyone or any process that executes the application will do so with the sysadmin's group permissions.

Question 26 Which directory contains information about each kernel module installed on the computer? (Tip: Enter the full path to the directory.)

/Sys/module Explanation The /sys/module has a sub-directory for each kernel module installed on the computer. The /sys directory contains information about devices and drivers. In addition to the /sys/module directory, be aware of the following directories in /sys:

Question 3 Under the Filesystem Hierarchy Standard (FHS), which directory contains information about the system state and processes7 /tmp /bin /root /proc

/proc Explanation Under the Filesystem Hierarchy Standard (FHS), the /proc directory contains information about the system state and processes. The Filesystem Hierarchy Standard (FHS) governs the unified file system for Linux systems by defining a standard set of directories, subdirectories, and files.

Question 50 What is the priority of the gedit process after using the nice gedit command? 10

10 Explanation nice gedit starts the gedit process with a priority of 10. Use nice -n to specify the priority value. If no value is specified, the process starts with 10 as the default.

Question 24 How many primary partitions can you create on a single hard disk drive? s 4 2 Unlimited

4 Explanation There can be a maximum of four primary partitions on a single hard disk drive. A partition is a logical division of a storage device associated with a hard disk drive. A primary partition is one that is used to store the operating system. Primary

Question 9 Which of the following sets of octal permissions would allow everyone to execute the following file as if they were the root user?

4755 Explanation File permissions can be displayed in a number of ways. The traditional method is rwxrwxrwx. With this method the r means read, the w means write and the x means execute. These permissions are displayed for the user owner (first set), group owner (second set) and the world or everyone (third set). Permissions can also be converted into binary using 3 bits; one for read, one for write and one for execute. In this notation rwxrwxrwx would be 111111111. Displaying the permissions in binary is a bit long-winded so binary permissions are often converted into octal numbers (digits 0-7). In octal rwxrwxrwx would be represented as 777 (111 binary = 4+2+1 = 7 octal). A fourth group of rwx (111 binary or 7 octal) can be appended to the beginning of the permissions to set SUID (100 binary or 4 octal), SGID (010 binary or 2 octal) and/or the sticky bit (001 binary or 1 octal). This would be represented as 0777 octal if none of these are set. 0755 is incorrect because even though everyone can execute the file it will be executed with the permissions of the user that executes it. 4744 is incorrect because even though the SUID bit is set only the user owner can execute it. 1655 is incorrect because the group owner and everyone can execute it but it will be executed with the permissions of the user that executes it.

Question 31 You are called into the office of a newly hired manager. He has copied a file from his old place of work onto his new workstation, but is now receiving an error message that access is denied each time he tries to access the file. He is not the owner of the file, and not a member of the group the file is associated with. Which of the following represents the least set of file permissions needed for him to be able to read and write to the file? 111 222 444 666

666 Explanation Because he is not a member of the group, or the owner of the file, the only set of permissions applying to the manager is the last number. The ability to read the file has a value of 4, while the ability to write to the file has a value of 2. Adding the two together, the needed permission for the user is 6.

Question 29 After opening a file in vi, you want to switch from command mode to command line mode. What key should you enter>

: Explanation Typing: enters command line mode from command mode. Vim has the following modes:

Question 28 Which key combination should you press in vi to save the file you are working on and quit? q s s wq

:wq Explanation To enter command mode, you must press the colon (:) followed by the actions you want to take. The actions to take in this case are to write the file (save it), and quit.

Question 10 Which of the following commands will configure the shell to retain 300 recently-used commands in the IV/ .bash_history file for multiple shell sessions? HISTFILESIZE=300 HISTSIZE=300 HISTFILE=300 BASH=300

@ HISTFILESIZE=300 Explanation Use HISTFILESIZE=300 to specify the number of past commands remembered between sessions. The HISTFILESIZE environment variable specifies the number of past commands remembered for the current session. The HISTFILE environment variable specifies the filename where past commands are remembered. The BASH environment variable specifies the location of the bash executable file.

Question 52 Match the vim mode on the left to the correct definition on the right. Edit mode command mode command line mode The initial vim mode used when vim is started. It has commands that cut and replace text, and it is the mode vi uses to enter the other modes. The mode that works with the file system. Use it to save files after editing them. The mode that vim uses to write and edit text in the file. IEdit mode

Command Mode>>The initial vim mode used when vim is started. It has commands that cut and replace text, and it is the mode vi uses to enter the other modes. Command Line Mode>>The mode that works with the file system. Use it to save files after editing them. Edit Mode>>The mode that vim uses to write and edit text in the file. IEdit mode

Question 43 Match the correct term on the left with the definition on the right. D-BUS I hald /udev SYSfS Allows processes to communicate with each other and notify them of new hotplug devices Provides all applications with data about current hardware Dynamically creates device files in a virtual file system as devices are added and removed Exports information about hotplug devices so that other utilities can access the information

D-BUS I >>Allows processes to communicate with each other and notify them of new hotplug devices hald >>Provides all applications with data about current hardware /udev>>Dynamically creates device files in a virtual file system as devices are added and removed SYSfS >>Exports information about hotplug devices so that other utilities can access the information

Question 49 Which daemon allows processes to communicate which each other and relay information about hotplug devices? hald udev sysfs D-Bus

D-Bus Explanation The Desktop Bus CD-Bus) daemon allows processes to communicate with each other and notify them of new hotplug devices. The Hardware Abstraction Layer (HAL) daemon (hald) provides all applications with data about current hardware. sysfs is a virtual file system mounted at /sys which exports information about hotplug devices so that other utilities can access the information. udev is a virtual file system that dynamically creates device files as devices are added and removed.

Question 2 You are installing a boot loader on a system that will boot both Linux and Windows. You are going to use the GRUB boot loader for Linux. Where is the best location for GRUB7 Pick the most correct answer. GRUB should be installed on the boot sector of the Linux partition. You can't use GRUB in a Windows/Linux environment. GRUB should be installed on a floppy disk. GRUB should be installed on the MBR of the first fixed disk.

GRUB should be installed on the boot sector of the Linux partition. Explanation In a mixed as environment GRUB should be installed in the Linux partition not the MBR where it can be overwritten.

Question 20 Which symbol uses the output of one command as the input of another command?

I Explanation The pipe (I) symbol directs the output of one command into the input of another command.

Question 42 Which of the following statements best describe the purpose of the Filesystem Hierarchy Standard (FHS)? (Select two.) During installation, software can determine the permissions of specific directories. Individual users can predict where to find system configuration files. During installation, software can predict where to place configuration files. As users create files, they are forced to place the files in specific directories.

Individual users can predict where to find system configuration files. During installation, software can predict where to place configuration files. Explanation The Filesystem Hierarchy Standard (FHS) governs the unified file system for Linux systems by defining a standard set of directories, subdirectories, and files. Among other benefits, FHS allows:

Question 53 Which of the following commands will display information about the PCl devices installed on the system? Ismod Isusb Ispci hwinfo

Ispci Explanation Use the Ispci command to display information for all PCI devices installed on the system. Be aware of the following options: Isusb displays information on all USB devices connected to the computer. hwinfo displays information about hardware on the computer. Ismod displays information about all loaded modules on the system.

Question 7 Which command reads from standard input and writes to standard output and files?

Itee I Explanation The tee command reads from standard input and writes to standard output and files.

Question 1 What is the result of the apt-get -d command? The package database is checked for consistency and errors. Package installation is simulated without an actual installation. All installed packages are upgraded to the latest versions in with the information in /etc/apt/sources.list. Packages are downloaded to the system, but not installed.

Packages are downloaded to the system, but not installed. Explanation The apt-get command downloads and installs packages. The apt-get -d command downloads packages without installing them.

Question 5 What is the full path for the Yellowdog Updater Modified (YUM) configuration file? (Tip: Enter the full path.)

Question 5 What is the full path for the Yellowdog Updater Modified (YUM) configuration file? (Tip: Enter the full path.) l/etc/YUm.conf I

Question 27 You are assembling a workstation. The system requirements show that this system will be used primarily to store documents of small size. What is the best Linux filesystem to install? Ext2 ReiserFS HPFS Ext3

ReiserFS Explanation The ReiserFS is more efficient at storing small files than most file systems. Ext2 and Ext3 store small files less efficiently than ReiserFS. HPFS is more efficient for storing files than most filesystems but is not a Linux filesystem.

Question 33 What will be the effect of the following command? Is -I /usr/bin » /tmp/list.txt The contents of the /usr/bln directory will be appended to the file called /tmp/list.txt and then the contents of / tmp/list.txt will be output to the screen. The contents of the /usr/bin directory will be redirected into a file called /tmp/list.txt, inserted before the previous contents of the file. The contents of the /usr/bin directory will be redirected into a file called /tmp/list.txt, inserted after previous contents of the file. The contents of the /usr/bln directory will be redirected into a file called /trnp/llst.txt, overwriting the previous contents of the file.

The contents of the /usr/bin directory will be redirected into a file called /tmp/list.txt, inserted after previous contents of the file. Explanation The> > will redirect the output of a command, appending it to another file. The> will redirect the output of a command into another file overwriting the previous contents of the file. Neither command will redirect the output of a command to the screen.

Question 60 You have a system with more than one Linux operating system installed. During the system's bootup process, which component loads a splash screen, thus allowing you to choose which operating system you want to run? The initial program The primary boot loader BIOS The secondary boot loader

The secondary boot loader Explanation The secondary boot loader provides a splash screen allowing you to choose which operating system you want to load. This occurs in the boot loader stage of the boot process. Specifically, During the boot loader stage, the following steps take place:

Question 25 Which statement is correct on how to differentiate core processes from other services? (Select two.) In Linux all processes have the same permissions and there are no core processes. They have the lowest pid numbers, always below 100. If you run ps -aux, the core processes are at the top of the listing. When you run top, the processes with the most cpu time are core processes. They have the higher pid numbers, always above 100.

They have the lowest pid numbers, always below 100. If you run ps -aux, the core processes are at the top of the listing. Explanation Core processes always have the lowest pid numbers and are always at the top of a ps -aux listing. Linux has core processes that control or spawn all other services.

Question 12 Which of the following devices represent a hotplug device? USB flash drives CPU (Central Processing Unit) PCI Express cards RAM (Random-access Memory) chips

USB flash drives Explanation The USB flash drive represents a hotplug device. Hotplug devices can be removed while the computer is on. Linux uses software designed to detect these changes as the devices are added and removed. Hotplug devices also include FireWire devices.

Question 51 You are using awk to print a sorted list of the user names in /etc/passwd. Which command will accomplish the sorted output? awk -F: '{print $1}' /etc/passwd I sort awk -F: '{print $2}' /etc/passwd I sort awk '{print $1}' /etc/passwd I sort awk '{print $A}' /etc/passwd I sort

awk -F: '{print $1}' /etc/passwd I sort o awk -F: '{print $2}' /etc/passwd I sort o awk '{print $1}' /etc/passwd I sort o awk '{print $A}' /etc/passwd I sort Explanation The -F: indicates that the file separator is a colon (:), the separator that is used in the /etc/passwd file. The string '{print $1}' allows the command to print column number 1 (column numbers start at 0). The $A is incorrect because AWK needs a column number (numeric) not an alpha. The string /etc/passwd represents the file to process and the string I sort pipes the print output to the sort routine.

Question 22 Which of the following commands will display which boot options were given to the kernel at boot time? cat /proc/cmdline cat /proc/modules cat /proc/mounts cat /proc/version

cat /proc/cmdline Explanation Use cat /proc/cmdline command to display the boot options given to the kernel at boot time. The /proc directory contains information about the system state and processes.

Question 59 Which of the following commands will give the same results as cat < turbo? cat turbo cat 2> turbo cat 1> turbo cat 1&2> turbo

cat turbo Explanation The cat turbo command performs the same function. The default operation of the cat utility is to read and display a file. (You get the same result whether you use the input operator or not.)

Question 39 Which command will change the group ownership for the devstyle.txt file to rand in the present working directory? (Tip: Enter the command as if at the command prompt.)

chgrp rand devstyle.txt Explanation Use chgrp rand devstyle.txt to change the group ownership for the devstyle.txt file to rand. The chgrp command changes the group owner of a file or directory. chown can also change the group ownership. The following chown commands change the group ownership as required in the scenario:

Question 4 You are requested to help a user who reports that he has no more local storage space. You go to his system and log in as root user. Which command will display the available disk space on all partitions? (Choose two.) df du-a dskuse -free du-h fdisk -free df-h

df df-h Explanation The command df shows the size, used and available blocks for each partition. Using df -h shows the same information in bytes instead of blocks. The command du is used to show the disk usage of each file in a directory in blocks: du -a is for all files, and du -h shows the usage in bytes not blocks. Fdisk is used for partitioning a drive. There is no command called dskuse.

Question 38 Which dpkg option lists information about a currently installed Debian package? (Tip: Enter the command as if at the command prompt.)

dpkg -p Explanation The dpkg command installs Debian packages on Debian distributions. The dpkg -p command lists information about a currently installed Debian package. Be aware of the other following options:

Question 32 Which command shows the value of the environmental variable currently set for the terminal? echo $TERM echo %TERM echo TERM echo %TERM%

echo $TERM Explanation Use the echo command to see the value of a variable. To specify an environmental variable, precede the name of the variable with a dollar sign ($).

Question 56 Which command should you use to change the quota settings for the gshant user? (Tip: Enter the command as if at the command prompt.)

edquota -u gshant

Question 41 You want to restore files with the extension .cfg from an archive called configs.cpio. Which command will perform the restore? epio -ivd "*.cfg" < /mnt/hdd2/configs.cpio cpio -ivd /mnt/hdd2/configs.cpio < "*.cfg" epio -ivd "cfg" < /mnt/hdd2/eonfigs.cpio epio -ivd ".efg" < /mnt/hdd2/eonfigs.epio

epio -ivd "*.cfg" < /mnt/hdd2/configs.cpio Explanation The correct command is epio -ivd "*.cfg" < /mnt/hdd2/eonfigs.epio. The cpio command processes one item at a time making the use of piped output, text files or multiple quoted items as input. The option i means extract, d means restore the files and directory path if the files were archived with a directory path and v is verbose mode.

Question 55 What is the result of the nohup gedit St command? (Select the most accurate statement.) gedit will start after logging out of the shell. gedit will start in the foreground and terminate after logging out of the shell. gedit will start in the background and persist in the background after logging out of the shell. gedit will start in the background and terminate after logging out of the shell.

gedit will start in the background and persist in the background after logging out of the shell. Explanation nohup gedit & starts the gedit process in the background and leaves it running after logging out of the shell. nohup:

Question 6 You recently installed a third hard drive in your system. You need to install GRUB on the hard drive. Which command should you use? grub-install --root-directory= /boot sdO grub-install --root-directory=/boot sdl grub-install --root-directory=/boot sd2 grub-install --root-directory=/boot sd3

grub-install --root-directory=/boot sd2 Explanation Use grub-install --root-directory=/boot sd2 to install GRUB on the third hard drive.

Question 45 You are working with the following RPM package: acroread-8.1.3-51.6.i586.rpm. Drag the naming convention term on the left to match the items on the right. Release number Package name Architecture type version number i586 8.1.3 acroread 51.6

i586 >>Architecture type 8.1.3 >>version number acroread >>Package name 51.6 >>Release number

Question 17 You are experiencing a problem with a network server. You want to bring the system down and try reseating the cards within it before restarting it. Which command completely shuts down the system in an orderly manner? initO init 1 init5 init6

initO Explanation Use the init utility to change runlevels.

Question 54 You need to view the contents of the /homefjerrys directory. Which command will show all the contents, including hidden files and directories? (Tip: Only include the necessary command options.)

is -a /home/jerrys I Explanation Use the Is -a command to view the contents of a directory, including the hidden content.

Question 16 Which file shows the currently mounted volumes? jetejmount.eont jetejmount jetejmtab j etejfstab

jetejmtab Explanation The jetejmtab file shows the currently mounted volumes. jetejtstab controls which volumes are mounted at boot. jetejmount and jetejmount.eont are not defined by FHS to show mounted filesystems.

Question 57 You have been called in to a remote site to troubleshoot a problem with a process that needs to be terminated. You are taken to the workstation having the problem and immediately realize that it is an implementation of Linux you have never worked with before. Which option would you use with the kill utility to see the valid signals available? (Tip: Enter the command as if at the command prompt.)

kill -I Explanation Use kill -I to list all of the signals that are available for the kill command.

Question 47 You need to find a specific file on your Linux system. Which of the following commands should you use? (Select two. Each answer represents an independent solution.) whereis which locate find

locate find Explanation Use find or locate to search through your file system to find files. Find searches through all files based on the file system by name, file size, time created, and other options. locate is much faster than find, and searches /var /Iog/ locatedb as the index file. Where is displays the path to the binary files, the manual pages, and the source code. which displays the path to a command and determines whether a package is installed.

Question 30 You are trying to debug a shell script called myscript and to aid you in this task you would like to have the output of the script be recorded in a text file. Which of the following commands would satisfy your requirements? myscript I testfile.txt myscript I echo I testfile.txt echo myscript » testfile.txt myscript »testfile.txt

myscript »testfile.txt Explanation myscript »testfile.txt is correct because the> > redirector redirects the output of a command, in this case a script called myscript, into a file echo myscript » testfile.txt is incorrect because only the line myscript would be redirected into a file called testfile.txt. myscript I testfile.txt is incorrect because a I redirects the output of a command to be the input of another command and not into a file. myscript I echo I testfile.txt is incorrect because even though the output of myscript is piped into echo the I after echo would not redirect the output into a file.

Question 37 Which of the following commands starts the gedit program with a priority 1 above the default nice priority? nice -n -20 gedit nice -n 1 gedit nice -n -19 gedit nice -n -1 gedit

nice -n -1 gedit Explanation nice -n -1 gedit starts the gedit process with a priority 1 above the default. Zero (0) is the default nice value for processes not executed with the nice command. The nice command start a command with a higher or lower priority.

Question 15 You have a computer configured with two installations of Linux. You are using the LILO boot loader, a portion of which is shown below. boot=/dev/hda map=/boot/map install=/boot/boot.b lba32 default=linux image=/boot/vrnlinuz-2.2.5-15 label=linux initrd=/boot/initrd-2.4.20-8.img read-only root=/dev/hda3 When the system boots, it moves immediately to the Linux installation without giving you a chance to choose an operating system. What should you add to lilo.conf to add the LILO prompt and a delay of 5 seconds? (Select all that is required.) prompt timeout=50 timeout=5 prompt=5 prompt=50

prompt timeout=50 Explanation To show the LILO: prompt with a delay, add: Both lines must exist. Using prompt by itself will stop the boot and wait for a selection. The timeout value is in tenths of a second, so 50 = 5 seconds.

Question 14 Which set of permissions represent the minimal permissions required to allow a user to list the contents of a directory? r-x r-- rw- rwx

r-x Explanation To list the contents of a directory, a user must have the read (r) permission and the execute (x) permission.

Question 48 Which command would you use to assign a new priority to a process that has already started? (Tip: Enter the command as if at the command prompt.)

renice Explanation renice assigns a new priority to a process that has already started using the PID of the process. The command can contain multiple PIDs separated by a space to give them all the same priority number. renice values range from 19(lowest priority), to -20 (highest priority.) The higher the number, the lower priority the job receives in the system.

Question 3S Which command will upgrade an RPM package only if an earlier version is already installed on the system?

rpm -F I Explanation The rpm -F upgrades the package, but only if an earlier version currently exists on the system.

Question 11 You have an RPM package called mathpac that is not working correctly. You have downloaded the latest package. Which line is the most correct option? rpm -U math pac rpm -F math pac First rpm -e math pac then rpm -i mathpac rpm -i math pac

rpm -U math pac Explanation The -U option specifies upgrade the package. Basically this is installing the new package and removing the old. rpm -F will freshen the current install, but still has a small possibility of not solving the problem. rpm -I installs a new package, which will not work in this case since the package is already installed.

Question 34 Which of the following utilities will substitute an existing string with a new string within a file? grep egrep fgrep sed

sed Explanation sed takes text as input and modifies the text document named in the command line. The sed s option replaces the text behind the first forward slash (I) with the text behind the second forward slash (I). grep, fgrep, and egrep do not modify files. grep searches through files for a specified character string. fgrep searches for fixed strings rather than regular expressions. egrep uses regular expressions in the search strings.

Question 8 You want to issue a simple command to replace all the occurrences of the string foo with the string bar in the file myfile.txt. You have decided to use sed. Which line will work? sed -e 'sub/foo/bar/glob' mytile.txt sed -e '/foo/bar/g' mytile.txt sed -e 's/too/bar/g' myfile.txt sed -e 's/too/bar/' mytile.txt

sed -e 's/too/bar/g' myfile.txt Explanation The sed -e 's/too/bar/g' myfile.txt command replaces all the occurrences of foo with bar in myfile.txt. The s means substitute. /foo/bar/ is the substitution string meaning substitute the first item, foo with the second item bar. The 9 means global. Lastly, the file to act on is mytile.txt.

Question 21 You created a swap area on sda3, but it is not activated. Which command should you use to activate the swap partition? (Tip: Enter the command as if at the command prompt.)

swapon /dev/sda3 I

Question 13 The MTS log file contains thousands of entries, but you are only interested in the most recent entries. Each time entries are added, they are appended to the end of the file. Which utility will be best suited for examining the entries you are interested in? tail head apropos locate

tail Explanation Use the tail utility to view the last lines in a file. By default, it shows the last ten lines, but you can specify another number to show if you need to see more or less than ten.

Question 44 You are trying to configure the Samba service and would like to view the output of the messages log in reel-time as it updates. Which of the following commands would produce the desired results? tail /var/log/messages tail -f /var/log/messages cat -f /var/log/messages less /var/log/messages

tail -f /var/log/messages Explanation Only tail with the -f (follow) switch will show the output in real-time. The commands less, cat, and tail will all display the contents of a file onto the screen. However, less displays the contents one page at a time, cat displays the contents all at once, and tail displays the last 10 lines of content.

Question 23 You need to backup Jane's files in her /home/user/jane directory. Which command will create an archive in the / root directory? (Select two.) tar -cbvf /root/jane.tbz /home/user/jane tar -cgvf /root/jane/tgz /home/user/jane tar -czvf /root/jane.tgz /home/user/jane tar -cjvf jane.tbz /home/user/jane tar -cvf /root/jane.tar /home/user/jane

tar -czvf /root/jane.tgz /home/user/jane tar -cvf /root/jane.tar /home/user/jane Explanation tar -cvf will create a standard archive, jane.tar, in the root directory. tar -czvf will create a compressed archive, jane.tgz, in the root directory. tar -cjvf does create a compressed archive (using bzipz), but not in the root directory. The command tar -cbvf is incorrect due to the -b switch and tar -cgvf is incorrect due to the -g switch.

Question 46 A user calls the help desk. Each time he creates a new text file, permissions of 640 are applied to the file and he must use chmod to set them to 644. What command should you enter in the user's profile to set the default permission for newly created files to 644? umask 640 umask -640 umask 0022 umask 0027

umask 0022 Explanation The user currently has an umask value of 0027, which is what is causing the new files to have permissions of 640. Changing this value to 0022 will allow all newly created files to have permissions of 644.

Question 36 Partition /dev/sdb2 is mounted to /mnt/temp. You need to unmount /dev/sdb2. Which commands would you use? (Choose two.) umount /mnt/temp dismount /mnt/temp unmount /dev/sdb2 umount /dev/sdb2 dismount /dev/sdb2

umount /mnt/temp umount /dev/sdb2 Explanation Use umount to unmount a device. You can specify the device, /dev/sdb2, or the mount point /mnt/temp. There are no utilities called unmount or dismount in Linux.