Linux commands for exam LPIC-1 - 101

Commands Explanation
uname -r Shows the kernel version (release)
uname -m Displays the system architecture
uname -a Displays all information that uname can output
lscpu Shows details about the CPU
lsmod Shows the running kernel modules
modinfo <module name> Displays detailed information about a kernel module
modinfo -a <module name> Shows the author of a kernel module
modinfo -d <module name> Shows a brief description of the kernel module
modinfo -l <module name> Shows the license under which the kernel module is located
modprobe <module name> Loads a kernel module into the kernel
modprobe -r <module name> Unloads a kernel module from the kernel
rmmod <module name> Unloads a kernel module from the kernel (out of date!)
insmod <path/module name> Loads a kernel module into the kernel (outdated!)
lspci Lists all PCI devices
lspci -v Lists all PCI devices in a more detailed view
lspci -vv / lspci -vvv Lists all PCI devices in an even more detailed view
lspci -k Lists all PCI devices, including the modules they use
lsusb Lists all USB devices
lsusb -v Lists all USB devices in a more detailed view
lsusb -s 002 Lists only the USB devices on bus 002
lsusb -d <vendor id> Only shows the USB devices of the respective manufacturer
lsusb -t Displays the USB devices in a tree view
pstree Shows running processes in a tree view
pstree -p Shows running processes including the process ID in a tree view
dmesg Reads the kernel ring buffer (kernel boot logs)
journalctl Displays all systemd logs
journalctl -k Displays all systemd logs related to the kernel
chkconfig --list Shows the services that are started automatically, including runlevel (init)
service <process> start Starts a process (on SysVinit systems)
service <process> stop Stops a process (on SysVinit systems)
service <process> status Shows the status of a process (on SysVinit systems)
initctl list Shows a list of all init services + their status
initctl start <process> Starts a process (on upstart systems)
initctl stop <process> Stops a process (on upstart systems)
initctl status <process> Shows the status of a process (on upstart systems)
systemctl start <process> Starts a process (on systemd systems)
systemctl stop <process> Stops a process (on systemd systems)
systemctl status <process> Shows the status of a process (on systemd systems)
systemctl list-units Lists all systemd units of the system including status
systemctl restart <process> Restarts a process (on systemd systems)
runlevel Shows in which runlevel you are currently and before
init 3 Changes to run level 3
telinit 3 Changes to run level 3
systemctl isolate multi-user.target Changes to the boot target Multi-User.Target (systemd)
systemctl get-default Displays the set standard boot target
systemctl set-default multi-user.target Sets the standard boot target to Multi-User.Target
systemctl isolate reboot.target Restarts the system
systemctl isolate poweroff.target Turns off the system
shutdown -r +10 Restarts the system in 10 minutes
shutdown -c Deletes the previously set waiting time and thus the entire command
shutdown -r now Immediately restart the system
shutdown -h now Shuts down the system immediately
halt Shuts down the system
poweroff Shuts down the system
reboot Reboots the system
wall <message> Sends a message through the system to logged-in users
swapon -s Displays the swap partitions or files in use
swapoff -a All swap files or swap partitions will be stopped
swapon -a Any swap files or swap partitions will start
lsblk Lists all block devices (hard drives)
df Lists all hard disks including storage space and mount point
blkid Displays the UUID of a hard drive
mount Shows all mounts of the system
pvs Displays the physical volume (PV) (with installed LVM)
vgs Displays the volume groups (VG) (if LVM is installed)
lvs Displays the logical volumes (LV) (if LVM is installed)
grub-install <grub partition> Installs GRUB Legacy in the corresponding GRUB partition
grub Opens a GRUB shell (legacy)
grub-mkconfig / grub2-mkconfig Creates a new grub.cfg file (GRUB 2). To do this, manual
Changes have been made in the / etc / default / grub file
update-grub Same function as grub-mkconfig, but only on debian systems
available
ldd /path/program Shows which libraries the respective program uses
ldconfig Makes new libraries known system-wide
LD_LIBRARY_PATH Variable in which a library path can be stored
dpkg -i <program.deb> Installs the program <programm.deb>
dpkg --configure <program> Configures the program <program> (usually not necessary because this
happens automatically during installation)
dpkg-reconfigure <program> Completely reconfigures <program>
dpkg -L <program.deb> Shows in which paths the program would be installed
dpkg -l Shows a list of all installed packages on the system
dpkg -r <program> Removes <program> from the system. Configuration files are retained!
dpkg -P <program> Removes <program> including configuration files
dpkg --purge <program> Removes <program> including configuration files
apt install ./<program.deb> Installs the <program.deb> downloaded in the current directory,
including the corresponding dependencies
apt purge <program> Removes <program> including all configuration files and dependencies,
provided they are not used by other programs
apt update Updates the package sources from /etc/apt/sources.list
apt dist-upgrade Updates the entire Linux system to the latest state
apt upgrade Updates the system but does not delete any files. So refuses
Service when a file should be deleted
apt full-upgrade Updates the system and also deletes files if necessary.
apt autoremove Deletes files that are no longer needed due to a system update
apt-cache search <program> Searches for <program> in the apt cache
apt-cache depends <program> Outputs the dependencies of <program> (before the installation!)
aptitude install <program> Installed <program> with aptitude
aptitude remove <program> Removes <program> from the system. Configuration files are retained.
aptitude purge <program> Removes <program> including configuration files from the system.
aptitude search <program> Searches for the package <program> in the aptitude cache
aptitude Starts the graphical user interface of aptitude
rpm -qpl <program.rpm> Shows in which paths the program would be installed
rpm -qpi <program.rpm> Displays detailed information on <program.rpm>
rpm -i <program.rpm> Installs <program.rpm> on the system (dependencies are not
resolved independently!)
rpm -qa Displays all programs installed on the system
rpm -e <program> Removes <program> from the system (e = erase)
rpm -U <program.rpm> Updates <program.rpm> to a newer version
rpm -qf /path/program Shows from which package /path/program originated
yum update Updates the entire system to the latest version (Red Hat systems)
yum search <program> Searches for <program> in the package sources
yum info <package name> Provides detailed information on <package name>
yum install <program> Installed <program> including all dependencies
yum list installed Displays all programs installed on the system
yum remove <program> Removes <program> from the system
yum autoremove Deletes files that are no longer needed due to a system update
yum whatprovides <program> Shows, among other things, which package <program> originally came from
yumdownloader <program> Downloads <program> without installing it at the same time
zypper se <program> Searches for <program> in the package sources (SUSE systems)
zypper install <program> Installed <program> including all dependencies (SUSE systems)
zypper remove <program> Removes <program> from the system
zypper list-updates Displays the updates available for the system
zypper update Updates the system to the current status
zypper repos Shows the configured package sources from zypper
man 2 <command> Displays man page 2 of <command>
man 4 <command> Displays man page 4 of <command>
history Displays a history of the most recently entered commands
HISTFILE Variable that contains the file in which the history is saved
~/.bash_history File in which the history is saved
echo $HISTFILE Outputs the content of the HISTFILE variable
echo -e Activates the possibility to output line breaks (\ n) or TAB (\ t), for example
env Shows the environment variables including their values in bash
set Shows further variables of the shell + different functions
set -x Switches on the debug mode of the shell
set +x Switches off the debug mode of the shell
unset VARIABLE Deletes a variable
bash Starts another bash in which we are located automatically (child process)
export VARIABLE Creates a variable that can also be used in child processes
cat file1 file2 > file3 Copies the contents of file1 and file2 to file3
less file1 Outputs the content of file1 page by page
head <file> Displays the first 10 lines of <file>
head -n 20 <file> Displays the first 20 lines of <file>
tail <file> Displays the last 10 lines of <file>
tail -n 20 <file> Displays the last 20 lines of <file>
tail -f Displays the last lines of <file> in real time
zcat <file.gz> Outputs the content of a gz-compressed file
bzcat <file.bz2> Outputs the content of a bz2-compressed file
xzcat <file.xz> Outputs the content of a xz-compressed file
nl <file> Opens the text file with line numbers
nl -b a <file> Empty lines are also given a line number
wc <file> Shows the number of lines and words in a document
wc -w <file> Only shows the number of words
wc -l <file> Only shows the number of lines
od <file> Creates a dump of <file> in octal notation
od -c <file> Creates a dump of <file> in "normal" notation
od -b <file> Creates a dump in binary notation from <file>
od -h <file> Creates a dump of <file> in hexadecimal notation
od -a <file> Creates a dump of <file> in ASCII notation
md5sum <file> Displays the hash value of <file>
md5sum -c <file> Compares the saved hash value from <file> with the hash value of the
Program and outputs a corresponding message
sha256sum <file> Displays the hash value of <file>
sha512sum <file> Displays the hash value of <file>
sort <table.csv> Sorts <table.csv> based on the first number
sort -n <table.csv> Sorts <table.csv> based on the whole number
sort -t "," -k3 <table.csv> Sorts <table.csv> based on the data in the third column
uniq <file.txt> Deletes identical lines from <file.txt> that are directly below each other
uniq -c <file.txt> Deletes identical lines from <file.txt> that are directly below each other
and at the same time shows how often these lines occurred
uniq --group <file.txt> Groups identical lines from <file.txt>
cat table.csv | tr ',' ';' Replaces the commas in table.csv with semicolons
cat table.csv | tr -d ',' Removes the commas from table.csv
cat table.csv | tr 'a-z' 'A-Z' Replaces lower case letters in table.csv with upper case letters
cut -d ',' -f 4 table.csv Outputs only the fourth column of table.csv
cut -d ',' -f 1,2,4 table.csv Outputs columns 1, 2 and 4 of table.csv
paste <file1> <file2> Outputs the content of both files separated by TAB (standard)
paste -d ';' <file1> <file2> Outputs the content of both files separated by a semicolon
paste -d ';' -s <file1> <file2> Outputs the content of both files line by line, separated by a semicolon
sed 's/colleague/employee/g' tabelle.csv Replaces the word "colleague" in table.csv with the word "employee"
sed -i 's/colleague/employee/g' Replaces the word "colleague" in table.csv with the word "employee".
tabelle.csv This is saved directly in table.csv.
split -b 1000 <file> Creates several small files of 1000 bytes each from a large file
pwd Shows the directory in which you are currently located
cd /path/to/directory Changes to /path/to/directory
cd .. Changes back one directory in the directory tree
cd ~ Changes to the personal home directory
cd - Change to the directory you were in before
cp <file> /tmp Copies <file> to /tmp
cp -i <file> /tmp Copies <file> to /tmp. If the file already exists there, we asked if we want to
overwrite this
cp -p <file> /tmp Copies <file> to / tmp while keeping the time stamp of the source file
cp -r /tmp . Copies the directory / tmp including files and subdirectories into the
Directory in which we are currently
mv <file> /tmp Moves <file> to the / tmp directory
mv file1 file2 Renames file1 to file2
touch file Creates an empty file named "file" or changes the timestamp of a already
existing file "file"
touch -t 201904011234.21 <file> Sets the timestamp of <file> to 04/012019 at 12:34 p.m. and 21 Seconds
file <file> Shows what kind of file it is (e.g. ASCII text file)
ls Lists the contents of a directory
ls -a Lists the contents of a directory, including hidden files
ls -l Lists the contents of a directory in a detailed view (File permissions, owner,
size, etc.)
ls -lh Lists the contents of a directory in a detailed view. The size of files is
displayed in a readable format, e.g. 1 MB instead of 1000000 bytes
ls -R Shows the content of a directory, including the subdirectories
ls -ltr Sorts the output according to the files last edited. The last edited file is at the
bottom
mkdir test Creates a directory called "test"
mkdir test1 test2 test3 Creates three directories "test1-3"
mkdir -p test4/test5/test6 Creates the directory "test4" and the subdirectory "test5" and its
 Subdirectory "test6"
rmdir <directory> Deletes (empty) directory
rmdir -p <directory1/directory2> Deletes <directory 1> and its sub-folder <directory 2>
rm <file> Deletes <file>
rm -i <file> Before deleting, asks whether we are really sure
rm -v <file> Deletes <file> and then issues a success message
rm -f <file> <file> is deleted without asking
rm -rf ./<directory> Deletes <directory> including subfolders and files
find -name <filename> Searches (and finds, if available) <filename>
find /var -name *.log Looks for files with the extension .log in the /var directory
find / -maxdepth 4 -name *.log Searches in / for log files, but only with a maximum of 4 subdirectories
dd if=/dev/sda1 of=/dev/sdb1 Creates an exact image from /dev/sda1 to /dev/sdb1
dd if=/dev/sda of=backup_bootloader Creates a backup of the bootloader
bs=512 count=1
tar -cf file.tar file1 file2 Creates the archive file.tar from the files file1 and file2
tar -tf file.tar Displays the content of the file.tar archive without unpacking it
tar -rf file.tar file3 Inserts file3 into the existing archive file.tar
tar -xf file.tar Extract the archive file.tar
tar -xvf file.tar Extracts the archive file.tar and outputs a result
tar -cvzf file3.tar.gz file1 file2 Creates a gzip-compressed archive called file3.tar.gz from file1 and file2
tar -tzf file3.tar.gz Shows the content of the archive file3.tar.gz compressed with gzip
tar -xzvf file3.tar.gz Unpacks the gzip-compressed archive file3.tar.gz
tar -cvjf file4.tar.bz2 file1 file2 Creates a bzip2-compressed archive named file4.tar.bz2 from file1 and file2
tar -tjf file4.tar.bz2 Shows the content of the archive file3.tar.gz compressed with bzip2
tar -xjvf file4.tar.bz2 Unpacks the bzip2-compressed archive file4.tar.bz2
tar -cvJf file5.tar.xz file1 file2 Creates an xz-compressed archive called file5.tar.xz from file1 and file2
tar -tJf file5.tar.xz Shows the content of the archive file5.tar.xz compressed with xz
tar -xvJf file5.tar.xz Unpacks the xz-compressed archive file5.tar.xz
ls | cpio -o > content.cpio Lists the files of the directory in which we are located and directs forward
this to the cpio command in copy out mode. This then creates the packed file
content.cpio
cpio -i < content.cpio Extracts the content.cpio file
cpio -it < content.cpio Displays the content of the content.cpio file without extracting it
find . -depth | cpio -pd /tmp/test Searches for all subdirectories and files in the current directory and sends the
result to cpio. This is called in pass through mode and copies the files to the
/tmp/test directory that is created, if not yet available
gzip file1 Compresses file1 to file1.gz
gzip file1 file2 Compresses file1 to file1.gz and file2 to file2.gz
gzip -k file4 Compresses file4 to file4.gz without deleting file4 afterwards
gzip -d file1.gz Extracts file1.gz to file1
gzip -dk file2.gz Extract file2.gz to file2 without deleting file2.gz afterwards
gunzip file3.gz Extracts file3.gz to file3
bzip2 file1 Compresses file1 to file1.bz2
bzip2 -dk file1.bz2 Extract file1.bz2 to file1 without deleting file.bz2 afterwards
bunzip2 file1.bz2 Extracts file1.bz2 to file1
xz file1 Compresses file1 to file1.xz
xz -k file22 Compresses file2 to file2.xz without deleting file2 afterwards
xz -d file2.xz Extracts file2.xz to file2
unxz file2.xz Extracts file2.xz to file2
ls *.txt Shows all files in the current directory that have the file extension .txt in use
ls test* Displays all files in the current directory that start with the word test
ls ?.txt Shows all files in the current directory whose names consist of only one
Letter and have the file extension.txt
ls ??.txt Displays all files in the current directory whose names consist of just two
Letters and have the file extension.txt
ls [tT]est*.csv Lists files that begin with test or test and have the file extension .csv
ls test[1-4].txt Lists all files that begin with test and immediately afterwards a 1, 2, 3
or 4 follows
ls test[^1-2] Lists all files that begin with test and immediately thereafter NONE 1 or
2 follows
ls {table,chair}* Lists files that begin with the word table or chair
ls {table,test}[^1-2]*.[Tt][Xx]? Lists files that begin with table or test, but not with a 1 or 2 continue. The file
extension must begin with T or t and continue with X or x plus any other
character
ls -la / > list.txt Saves the result in the file list.txt. Possibly previously existing content
this file will be overwritten / deleted
ls -la /bin >> list.txt Saves the result in the file list.txt. Previously existing content becomes
thus not deleted. The new content is simply attached to the back
ls -la 1> liste2.txt Forwards the result to the standard output channel. 1 = STDOUT. In in this
case it is the file liste2.txt
ls -zb 2> error.txt Redirects the STDERR channel to error.txt. I.e. if ls -zb an error outputs, the
error output is saved in the error.txt file
ls -la > liste.txt 2> error.txt The result is redirected (STDOUT) to the liste.txt file. Possible Error
messages (STDERR) are redirected to the error.txt file
ls -la > liste3.txt 2>&1 Redirects both STDOUT and STDERR to the liste3.txt file
wc -l < file1 STDIN is not the keyboard at this point, but the file1 that we are at forward
the command wc -l
wc -l file1 Here we have used the keyboard as the STDIN. The result is the same as with
the STDIN redirection from a file
wc -l 0< file1 STDIN is not the keyboard at this point, but the file1 that we are at forward
the command wc -l. This is just a different Notation. 0 = STDIN
wc -l << HEREDOC Opens an interactive mode in which you can write commands / texts until the
word HEREDOC is written
tr 'a-z' 'A-Z' <<< $VARIABLE The content of the variable is passed on to tr. tr ensures that the Result is
output in capital letters
ls -la | tee list4.txt Outputs the result of ls -la on the screen and writes it as well also in the file
list4.txt
ls -la | tee -a list4.txt Outputs the result of ls -la on the screen and writes it as well also in the file
list4.txt. The old content will not be overwritten.
find *.bak | xargs Lists all .bak files side by side
find *.bak | xargs rm Deletes all .bak files in the corresponding directory
cat xargs-file | xargs Returns the words from the file xargs-file side by side
xargs -a xargs-file Returns the words from the file xargs-file side by side
xargs -a employees.txt | tr 'AZ' 'a-z' > The employee abbreviations in the employees.txt file are no longer
employees2.txt written one below the other, but side by side. The result is passed to tr
which converts the uppercase letters to lowercase letters. The result is saved
in the file employees2.txt
ps -ef Shows all processes that are currently active (detailed)
pstree Shows all processes in a tree view
pstree -p Shows all processes in a tree view, including process ID
top Dynamic overview of all running processes
top -p 1127,1128 Opens the top program, which in turn only displays the processes with
process IDs 1127 and 1128
free Shows statistics on RAM and SWAP memory
free -m Shows the RAM and SWAP data in megabytes
free -g Shows the RAM and SWAP data in gigagytes
free -b Shows the RAM and SWAP data in bytes
free -h Shows the RAM and SWAP data in the "best" readable format
pgrep nginx Displays the process ID of nginx
pgrep -l nginx Displays the process ID and name of the nginx process
kill -l Displays all possible kill signals
kill 1152 1153 Sends the SIGTERM (15) signal to processes 1152 and 1153, resulting in
leads to an orderly shutdown
kill -SIGTERM 1152 1153 Sends the SIGTERM (15) signal to processes 1152 and 1153, resulting in
leads to an orderly shutdown
kill -15 1152 1153 Sends the SIGTERM (15) signal to processes 1152 and 1153, resulting in
leads to an orderly shutdown
kill -TERM 1152 1153 Sends the SIGTERM (15) signal to processes 1152 and 1153, resulting in
leads to an orderly shutdown
kill -9 1152 Sends the SIGKILL (9) signal to process 1152, causing the Process is
rigorously killed
kill -SIGSTOP 1152 Sends the SIGSTOP (19) signal to process 1152, causing the process to be
stopped / paused
kill -SIGCONT 1152 Sends the SIGCONT (18) signal to process 1152, which results in the paused
process is continued
pkill -x nginx Sends the SIGTERM (15) signal to the process with the exact name "nginx"
killall -l Shows all signals that killall can send
killall -u manuel Kills all processes that run under the user Manuel
STRG+Z Sends the SIGSTOP (19) signal to the process currently running in the
foreground
fg Brings a process paused with SIGSTOP (19) back to the foreground
(Process starts again)
bg Brings a process paused with SIGSTOP (19) into the background (process
starts again)
STRG+C Sends the SIGINT (2) signal to the process currently in the foreground
running, which leads to the terminal connection of the process
interrupted and this is stopped
sleep 500 & Starts the sleep program with 500 seconds in the background
jobs Shows the processes in the background
nohup sleep 1000 & Starts the sleep program with 1000 seconds in the background. At the
If you log off from the system, the program continues and will not go through
SIGHUB (1) ended
watch uptime Runs the uptime program every 2 seconds
watch -n 5 uptime Runs the uptime program every 5 seconds
nice -n 5 sleep 1000 & Runs the sleep program with 1000 seconds in the background and assigns
the nice value 5
nice sleep 2000 Starts the sleep program with 2000 seconds and a nice value of 10
(10 = standard)
renice 2 -p 4512 Assigns a new nice value (2) to a process that is already running with the
Process ID 4512
renice 1 -u manuel Gives all processes that run manually under the user a new nice value (1)
ps -efo pid,ni,cmd Shows a table with running processes including PID and nice value
grep manuel /etc/passwd Searches the /etc/passwd file and prints all lines that start with the name
manuel
grep -v manuel /etc/passwd Searches the /etc/passwd file and prints out any lines that do NOT include the
Name manuel
grep -vn manuel /etc/passwd Searches the /etc/passwd file and prints out any lines that do NOT include the
Name manuel. In addition, line numbering inserted
grep -o manuel /etc/passwd Searches the /etc/passwd file and only outputs the words / names that you
was looking for, so in this case manuel
grep -i "^this" regex.txt Searches the regex.txt file for the word "this", which is, however must be at
the beginning of the line.
grep -i "example$" regex.txt Searches the regex.txt file for the word "example", which must be at the end
of the line
grep -i "example.$" regex.txt Searches the regex.txt file for the word "example" +1 anything Character,
which must be at the end of the line
grep -i "example\.$" regex.txt Searches the regex.txt file for the word "example" and a following point
(must again be at the end of the line)
grep -E "wonder(ful|bra)" regex.txt Searches the regex.txt file for the words "wonderful" or "wonderbra". grep
must be used in extended mode (-E / egrep)
egrep "wonder(ful|bra)" regex.txt Searches the regex.txt file for the words "wonderful" or "wonderbra". grep
must be used in extended mode (-E / egrep)
egrep -v "wonder(ful|bra)" regex.txt Searches the regex.txt file for everything except the words "wonderful"
and "wonderbra"
fgrep "wonder(ful|bra)" regex.txt Durchsucht die Datei gereg.txt genau nach "wonder(ful|bra)".
vi Starts the vi text editor
vi testfile vi starts and at the same time opens testfile or creates it, if it does not exist
:q Closes vi without saving first
:wq Saves and closes vi
:w Saves without closing vi
ZZ Saves and closes vi
:x Saves and closes vi
fdisk -l Lists all partitions
fdisk /dev/sdb Starts fdisk in interactive mode to edit the hard disk /dev/sdb
mkfs.ext4 /dev/sdb1 Writes the ext4 file system to the /dev/sdb1 partition
mkfs -t ext4 /dev/sdb1 Writes the ext4 file system to the /dev/sdb1 partition
lsblk -f Shows us the individual hard drives including file systems
mkfs.ext3 /dev/sdc1 Writes the ext3 file system to the /dev/sdc1 partition
mkfs.ext2 -j /dev/sdc1 Writes the ext3 file system to the /dev/sdc1 partition
mkfs /dev/sdd1 Writes the ext2 file system to the /dev/sdd1 partition
mkswap /dev/sdb1 Creates a swap partition (SWAP) in /dev/sdb1
swapon /dev/sdb1 Mounts the new SWAP partition /dev/sdb1 into the system
gdisk /dev/sdc Starts gdisk in interactive mode to edit the hard drive /dev/sdc
parted -l Shows the individual hard drives and their partitions
parted /dev/sdc Starts parted in interactive mode to edit the hard disk /dev/sdc
du / Lists the space used by each file
du -hs / Lists the total used space
du -hs /usr Displays the used space of /usr
du -h --max-depth=4 /home Shows the used space of the files and directories of /home, up to a maximum
of 4 subfolders
df -i Shows the inodes of the partitions
fsck /dev/sdc1 Checks the file system on /dev/sdc1 for errors if /dev/sdc is not mounted
mke2fs -t ext4 /dev/sdc1 Creates an ext4 filesystem on /dev/sdc1
tune2fs -l /dev/sda1 Outputs the current file system values
tune2fs -c 100 /dev/sda1 Sets the maximum mount count of /dev/sda1 to the value 100
tune2fs -T 20200501 /dev/sda1 Specifies the last time a file system check was performed
tune2fs -i 5d /dev/sda1 Specifies that a file system check should be carried out every 5 days
xfs_repair -n /dev/sdd1 Checks the XFS file system on /dev/sdd1 and lists errors without repairing
them
xfs_repair -v /dev/sdd1 Checks the XFS file system on /dev/sdd1 and repairs errors
xfs_db /dev/sdd1 Starts the interactive mode of xfs_db
xfs_fsr /dev/sdd1 Improves the organization of data in the file system of /dev/sdd1, similar
like a defragmentation
mount -t ext4 /dev/sdb1 /mnt/newhdd Mounts the partition /dev/sdb1 as ext4 to /mnt/newhdd
umount /dev/sdb1 Unmounts the /dev/sdb1 partition
umount /mnt/newhdd Unmounts the /dev/sdb1 partition
mount -a Mounts all partitions listed in the /etc/fstab file
blkid Outputs the UUID, labels, types and PARTUUID of hard disks
systemctl status /hdd2 Queries the status of the mount point /hdd2
systemctl stop /hdd2 Unmounts the hard drive / partition that is mounted to /hdd2
systemctl start /hdd2 Mounts the hard drive / partition to /hdd2
chmod 664 file.4711 Gives the file 664 permission
chmod u=rwx,g=rx,o=rx file.4711 Gives the file 755 permission
chmod u=rwx,go=rx file.4711 Gives the file 755 permission
chmod g+w file.4711 Adds the Write (w) group permission to the file
chmod 1777 test Sets the sticky bit to the test directory. This means that everyone is only
allowed to delete their own files and not others, although they have full
control
chmod 4777 test.sh Sets the SetUID bit for the test.sh file. This allows a normal user to start the
script with root rights even though he is not root himself.
chmod 2777 test.sh Sets the SetGID bit on the test.sh file. This allows a user to use the script
with the permissions of the appropriate owner group
chown thomas:thomas file.4811 Sets the owner and the owner group of the file.4811 to thomas
chown :manuel file.4811 Only sets the owner group file file.4811 to manuel
chown -R thomas:thomas tar Sets the owner and owner group of the tar directory and all Subdirectories
and files on thomas
chgrp -R manuel tar Sets the owner group of the tar directory and all subdirectories and files on
manuel
umask -p Displays the current umask value
umask 0026 Changes the umask to the value 0026
umask -S Displays the current umask value