February 2023 - ILUG-D - lists.fsci.in

1D1C - ssh
by Dhanasekar 28 Feb '23

28 Feb '23

ssh - is a program for logging into a remote machine and for executing commands on a remote machine To access remote server $ ssh 192.168.122.50 $ ssh my.server.in To specify a username for SSH connection $ ssh username@hostname_or_ip $ ssh -l username@hostname_or_ip $ ssh -l user1(a)192.168.122.50 $ ssh -l user1(a)my.server.in To use a different port number for ssh connection $ ssh my.server.in -p 2222 $ ssh 192.168.122.50 -p 2222 To run a command on a remote server from a local computer $ ssh 192.168.122.50 rm ~/Desktop/test_file.txt To execute multiple commands using SSH on remote nodes $ ssh 192.168.122.50 command1; command2; command3 To make ssh to use protocol version 2 $ ssh -2 user1(a)192.168.122.50 To Print debug information $ ssh -v user1(a)192.168.122.50 To increase the level of verbosity $ ssh -vv user1(a)192.168.122.50 To get more level of verbosity $ ssh -vvv user1(a)192.168.122.50 To enable X11 forwarding with ssh command $ ssh -X ip_address $ ssh -X 192.168.122.50 To hide the error message $ ssh -q 192.168.122.50 To change any default value to other possible values during ssh $ ssh -o option=value ip_address $ ssh -o Port=2222 192.168.122.50 regards, T.Dhanasekar

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1D1C - ss
by Dhanasekar 27 Feb '23

27 Feb '23

ss - is used to dump socket statistics, and to investigate sockets To list all Connections $ ss To list Listening and Non-listening Ports $ ss -a To list Listening Sockets $ ss -l To list all TCP connections $ ss -t To list all listening TCP connections $ ss -lt To list all UDP connections $ ss -ua To list all listening UDP connections $ ss -lu To display PID of sockets $ ss -p To display summary statistics $ ss -s To display IPv4 and IPv6 socket connections $ ss -4 $ ss -6 To filter connections by port number $ ss -at '( dport = :22 or sport = :22 )' $ ss -at '( dport = :80 or sport = :80 )' $ ss -at '( dport = :ssh or sport = :ssh )' $ ss -at '( dport = :http or sport = :http )' regards, T.Dhanasekar

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computer spares/ parts
by PETER REGELOUS 26 Feb '23

26 Feb '23

Hi Mr Dhanasekar Nice to e-meet Are these items of use I have found 1 man who is gifting them! @ , motherboard, cooler, RAM , graphics cards , laptop PSU, 5v 9v 12v power bricks, modem What can we use these for ? Kind regards @ ukX Peter Regelous

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1D1C - split
by Dhanasekar 26 Feb '23

26 Feb '23

split - is used to split large files into smaller files syntax $ split {options} {file_name} {prefix} $ cat example.txt This is line 1 This is line 2 This is line 3 This is line 4 This is line 5 This is line 6 This is line 7 This is line 8 This is line 9 This is line 10 To split example.txt with verbose option $ split example.txt --verbose To split files with customize line numbers $ split -l5 example.txt --verbose To split files with file size $ split -b 4 example.txt --verbose (in bytes) $ split -b 2K <file_name> --verbose (in Kb) $ split -b 2M <file_name> --verbose (in Mb) $ split -b 1G <file_name> --verbose (in Gb) To create Split files with numeric suffix instead of alphabetic $ split -d example.txt --verbose x00 To split file with customize suffix $ split -l5 example.txt ilugc_file To generate n chunks output files $ split -n5 <file_name> To Prevent Zero Size Split output files $ split -n60 -e example.txt To create split output files of customize suffix length $ split -b 4 example.txt -a 3 $ split -b 4 example.txt -a 4 To split ISO file and merge it into a single file $ split -n5 ubuntu-22.04.iso Split_IS0_ it will split ISO file into 5 pieces To merge these files into a single $ cat Split_IS0_a* > ubuntu22.04_new.iso To verify the integrity of merge file using md5sum before split of iso $ md5sum ubuntu22.04.iso after split and merge $ md5sum ubuntu22.04_new.iso regards, T.Dhanasekar

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1D1C - source
by Dhanasekar 25 Feb '23

25 Feb '23

source - is a built-in shell command that reads and executes the file content in the current shell. syntax $ source [filename] [arguments] To pass commands and arguments $ cat example.txt free -h pwd date time uptime $ source example.txt To read variables from a file $ cat example.sh #!/bin/bash VAR1="a" VAR2="b" VAR3="c" create bash script $ cat sample.sh #!/bin/bash source example.sh echo "VAR1 is $VAR1" echo "VAR2 is $VAR2" echo "VAR3 is $VAR3" $ source sample.sh To refresh the current shell environment $ alias ll = 'ls -l' $ alias c = 'clear' $ c $ ll This command only works in the current shell session To make it permanent $ sudo nano ~/.bashrc alias ll = 'ls -l' alias c = 'clear' :x Refresh the current shell environment and make it permanent for the user $ source ~/.bashrc To make it system wide change $ sudo vim /etc/profile alias ll = 'ls -l' alias c = 'clear' :x # source /etc/profile regards, T.Dhanasekar

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1D1C - sort
by Dhanasekar 24 Feb '23

24 Feb '23

sort - is used to sort a file, arranging the records in a particular order. $ cat file.txt assam tamilnadu chattisgarh delhi gujarat himachal pradesh kerala bihar To sort arrange the file.txt $ sort file.txt To Save Output to File $ sort file.txt > sorted.txt To Check for Sorting in File $ sort -c file.txt To Sort Multiple Files $ sort file1.txt file2.txt To Sort in Reverse Order $ sort -r file.txt To Remove Duplicate Entries $ sort -u file.txt To Sort by Months $ ls -l > month.txt $ sort -Mk6 month.txt To Randomly Sort Data $ sort -R sorted.txt regards, T.Dhanasekar

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1D1C - snap
by Dhanasekar 23 Feb '23

23 Feb '23

snap - is used to install, configure, refresh and remove snaps $ sudo snap install snap-store To Install Snap Apps $ sudo snap install <package_name> To list Installed snaps $ snap list To Search for Snaps $ snap find <search_term> To update snaps $ snap refresh <package_name> To print which snap packages have available updates $ sudo snap refresh --list To downgrade Snaps $ sudo snap revert <package_name> To remove Snaps $ sudo snap remove <package_name> To remove a snap without generating a snapshot $ sudo snap remove <package_name> --purge To Disable Snaps $ sudo snap disable <package_name> To Enable a disabled snap $ sudo snap enable <package_name> To List All Running Services $ snap services To list the services of a single snap $ snap services <package_name> To Start, Restart, and Stop Snap Services $ sudo snap restart <package_name> $ sudo snap start <service_name> $ sudo snap stop <package_name> To prevent a snap service from starting on boot $ sudo snap stop --disable <service_name> To make a service to start on next boot $ sudo snap start --enable <service_name> To Download and Install Snap Apps Offline $ snap download <package_name> To display history of changes made to system $ snap changes To change to a different channel $ sudo snap refresh <package_name> --channel=<channel_name> $ sudo snap refresh youtube-dl --channel=stable regards, T.Dhanasekar

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1D1C - slogin
by Dhanasekar 22 Feb '23

22 Feb '23

slogin - is an alias for the ssh client, which is used to connect securely to a remote shell. To login to a remote server $ slogin 192.168.122.50 $ slogin user1(a)192.168.122.50 To login to remote server with port $ slogin -p 22 user1(a)192.168.122.50 To to login as user1 on the remote machine $ slogin -l user1 192.168.122.50 regards, T.Dhanasekar

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1D1C - sleep
by Dhanasekar 21 Feb '23

21 Feb '23

sleep - is used to delay for a fixed amount of time during the execution of any script syntax $ sleep number[suffix] To make sleep command without any suffix $ sleep 20s To display help options $ sleep --help $ cat sleep.sh #!/bin/bash echo "Waiting for 10 seconds..." sleep 10 echo "Task Completed" :x $ sh sleep.sh Waiting for 10 seconds... Task Completed sleep command in the terminal with other commands $ ll && sleep 20 && pwd && free -h regards, T.Dhanasekar

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1D1C - skill
by Dhanasekar 20 Feb '23

20 Feb '23

skill - is used to send signals to users and process To halt/stop user1 $ skill -STOP -u user1 To resume already halted user1 $ skill -CONT -u user1 To kill and logout user1 $ skill -KILL -u user1 To kill and logout all users $ skill -KILL -v /dev/pts/* To stop 3 users user1, user2, user3 $ skill -STOP user1 user2 user3 regards, T.Dhanasekar

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ILUG-D February 2023