- ILUG-D - lists.fsci.in

1D1C - tar
by Dhanasekar 25 Mar '23

25 Mar '23

tar - an archiving utility syntax $ tar <options> <files> To create an archive file $ tar -cvf myfile.txt /home/ilugc/ To create tar.gz Archive File $ tar cvzf mydoc.tar.gz /home/ilugc/Documents To create tar.bz2 archive file $ tar cvfj mydownloads.tar.bz2 /home/ilugc/Downloads To untar tar Archive file $ tar -xvf mydoc.tar To untar tar archive file in different location $ tar -xvf mydoc.tar -C /home/ilugc/Music/ To uncompress tar.gz Archive File $ tar -xvf mydoc.tar.gz To Uncompress tar.bz2 Archive File $ tar -xvf mydownloads.tar.bz2 To list Content of tar Archive File $ tar -tvf mydoc.tar To List Content tar.gz Archive File $ tar -tvf mydoc.tar.gz To List Content tar.bz2 Archive File $ tar -tvf mydownloads.tar.bz2 To Untar Single file from tar File $ tar -xvf files.sh.tar file.sh To Untar Single file from tar.gz File $ tar -zxvf backup.tar.gz backup.html To Untar Single file from tar.bz2 File $ tar -jxvf Python.tar.bz2 demo.py To Untar Multiple files from tar, tar.gz, and tar.bz2 File $ tar -xvf file.tar "file1" "file2" "file3" $ tar -zxvf myfile.tar.gz "file1" "file2" "file3" $ tar -jxvf myfiles.tar.bz2 "file1" "file2" "file3" To Extract Group of Files using Wildcard $ tar -xvf Python.tar --wildcards '*.py' $ tar -zxvf Perl.tar.gz --wildcards '*.pl' $ tar -jxvf Bash.tar.bz2 --wildcards '*.sh' To add files or directories to the existing tar archive files $ tar -rvf file.tar file.txt $ tar -rvf file.tar demo.py To Add Files or Directories to tar.gz and tar.bz2 Files $ tar -rvf file.tar.gz sample.txt $ tar -rvf Php.tar.bz2 sample.php To verify any tar or compressed archive file $ tar tvfW sample.tar To Check the Size of the tar, tar.gz, and tar.bz2 Archive File $ tar -czf - sample.tar | wc -c $ tar -czf - mydocs.tar.gz | wc -c $ tar -czf - mydownloads.tar.bz2 | wc -c To Exclude Files and Directories When Creating Tar File $ tar --exclude='example.txt' -zcvf file.tar.gz /home/ilugc $ tar --exclude='/home/ilugc/songs' -zcvf backup.tar.gz /home/ilugc To exclude files with specific file extensions when creating a tar archive file, $ tar --exclude='*.txt' -zcvf backup.tar.gz /home/ilugc $ tar --exclude='*.py' -zcvf backup.tar.gz /home/ilugc To remove File and Directory from Tar Archive $ tar --delete -f backup.tar.gz sample.txt $ tar --delete -f backup.tar.gz '/home/tecmint/songs' To extract Specific File Extension in Tar Archive $ tar -xvf backup.tar.gz --wildcards '*.mp4' regards, T.Dhanasekar

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1D1C - taskset
by Dhanasekar 24 Mar '23

24 Mar '23

taskset - is used to set or retrieve the CPU affinity of a running process To fetch the CPU Affinity of a Process $ pidof sshd $ taskset -p <PID_of_sshd> To get the CPU range of a process $ taskset -cp <PID_of_sshd> To change the CPU affinity of a process by assigning the new value to the PID of the existing process $ taskset -p 0x7 <PID_of_sshd> To Change CPU range $ taskset -cp 0,2 <PID_of_sshd> To set the CPU core $ taskset -c 3,5 sshd $ taskset -c 0-4 sshd regards, T.Dhanasekar

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1D1C - tail
by Dhanasekar 23 Mar '23

23 Mar '23

tail - output the last part of files To display the last 10 lines of a file $ tail /var/log/messages To Display the last N lines in a file $ tail -n 4 /var/log/messages To Print filename header $ tail -v example.txt $ tail -v /var/log/messages To Display the last n lines from multiple files $ tail -n 4 file1.txt file2.txt $ tail -n 4 /var/log/messages /var/log/apache2/access.log To Save the output of tail command to a text file $ tail -n 10 /var/log/apache2/access.log > output.txt To append to output.txt $ tail -n 10 /var/log/messages >> output.txt To monitor real-time log files $ tail -f /var/log/messages To use pipes $ tail -file.txt | sort $ tail /var/log/messages | sort $ tail /var/log/messages | tail -n 6 | sort To Print N number of bytes data from a file $ tail -c 500 /var/log/messages $ tail -c 10M /var/log/messages To print help options $ tail --help regards, T.Dhanasekar

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1D1C - tac
by Dhanasekar 22 Mar '23

22 Mar '23

tac - is used to concatenate and print files in reverse syntax $ tac [OPTION]... [FILE]... $ cat example.txt This is line 1 This is line 2 This is line 3 This is line 4 This is line 5 $ cat example1.txt This is msg 1 This is msg 2 This is msg 3 This is msg 4 This is msg 5 To print files in reverse $ tac example.txt To attach the separator before instead of after $ tac -b example.txt example1.txt To make the STRING as the separator $ tac --separator="STRING" example1.txt example.txt To interpret the separator as a regular expression $ tac -r example.txt example1.txt regards, T.Dhanasekar

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1D1C - systemd-machine-id-setup
by Dhanasekar 21 Mar '23

21 Mar '23

systemd-machine-id-setup - Initialize the machine ID in /etc/machine-id To clear the original “machine-id” $ sudo rm /etc/machine-id To create the new “machine-id” value $ sudo systemd-machine-id-setup To verify the new value of machine-id. $ cat /etc/machine-id regards, T.Dhanasekar

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1D1C - systemd-analyse
by Dhanasekar 20 Mar '23

20 Mar '23

systemd-analyse - Analyze and debug system manager To determine system boot-up performance statistics $ systemd-analyze To Print time required to boot the machine $ systemd-analyze time To Print list of running units ordered by time to init $ systemd-analyze blame To Print a tree of the time critical chain of units $ systemd-analyze critical-chain Output state serialization of service manager $ systemd-analyze dump Output SVG graphic showing service initialization $ systemd-analyze plot To List load directories for units $ systemd-analyze unit-paths To List exit status definitions $ systemd-analyze exit-status To Analyze security of unit $ systemd-analyze security regards, T.Dhanasekar

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1D1C - systemd
by Dhanasekar 19 Mar '23

19 Mar '23

systemd - is a system and service manager for Linux operating systems To find boot process duration $ systemd-analyze $ systemd-analyze time To analyze time taken by each process at boot $ systemd-analyze blame To analyze critical chain at boot $ systemd-analyze critical-chain To Determine the initial start-up transaction $ systemd --test To make not to pipe output into a pager $ systemd --test --no-pager To Dump understood unit configuration items $ systemd --dump-configuration-items To dump exposed bus properties $ systemd --dump-bus-properties regards, T.Dhanasekar

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1D1C - systemctl
by Dhanasekar 18 Mar '23

18 Mar '23

systemctl - Control the systemd system and service manager syntax $ systemctl [OPTION] [SERVICE] To start service $ sudo systemctl start mariadb.service $ sudo systemctl start sshd To stop service $ sudo systemctl stop mariadb.service $ sudo systemctl stop sshd To restart or reload service $ sudo systemctl reload mariadb.service $ sudo systemctl restart mariadb.service To reload a service default, but if reload is not available for that service. It will restart it $ sudo systemctl reload-or-restart mariadb.service To check status of service $ sudo systemctl status mariadb.service $ sudo systemctl status sshd To enable service $ sudo systemctl enable mariadb.service $ sudo systemctl enable sshd To disable service $ sudo systemctl disable mariadb.service $ sudo systemctl disable sshd To check Service is enabled or disabled $ sudo systemctl is-active mariadb.service $ sudo systemctl is-active sshd $ sudo systemctl is-enabled mariadb.service $ sudo systemctl is-enabled sshd To see the status of all services $ sudo systemctl list-units --type=service To List services by status $ sudo systemctl list-units --type=service --state=active $ systemctl list-units --type=service --state=running $ systemctl list-units --type=service --state=stopped $ systemctl list-units --type=service --state=enabled $ systemctl list-units --type=service --state=disabled $ systemctl list-units --type=service --state=failed To prevent service from starting $ sudo systemctl mask {servicename} To Kill a service with signal 15 $ sudo systemctl kill {servicename} To Kill a service with signal 9 $ sudo systemctl kill -s 9 {servicename} To Reboot $ sudo systemctl reboot To shutdown $ sudo systemctl poweroff To change default to GUI $ sudo systemctl set-default graphical.target To switch to multi-user.target $ sudo systemctl isolate multi-user.target To reload daemon $ systemctl daemon-reload To find version $ systemctl --version regards, T.Dhanasekar

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1D1C - sysctl
by Dhanasekar 17 Mar '23

17 Mar '23

sysctl - configure kernel parameters at runtime To view all current kernel parameters invoke the sysctl $ sudo sysctl -a To view the swappiness value $ sudo sysctl vm.swappiness $ sysctl kernel.hostname To Modify the Kernel Parameters $ sudo sysctl -w parameter=value To enable IPv4 packet forwarding $ sudo sysctl -w net.ipv4.ip_forward=1 To set a parameter permanently $ sudo sysctl -w net.ipv4.ip_forward=1 >> /etc/sysctl.conf To read values from file $ sudo sysctl -p /etc/sysctl.d/file_name.conf To print variable names without values $ sudo sysctl -N vm.swappiness To print values only of the given variable $ sudo sysctl -n vm.swappiness To read values from all system directories $ sudo sysctl --system To print version and help options $ sudo sysctl --version $ sudo sysctl --help regards, T.Dhanasekar

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1D1C - sync
by Dhanasekar 16 Mar '23

16 Mar '23

sync - is used to synchronize the data of the temporary memory to the permanent storage memory syntax $ sync [option] [file] To sync all the cached files to the permanent memory which belongs to the current user $ sudo sync To sync only file data, no unneeded metadata $ sudo sync -d /home/ilugc/file1.txt To sync all the files in dir $ sudo sync -f /home/ilugc/Downloads To sync the cache data of the mounted partition $ sudo sync /dev/vda1 $ sudo sync /var/log/syslog regards, T.Dhanasekar

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