- ILUG-D - lists.fsci.in

1D1C - sudoreplay
by Dhanasekar 15 Aug '23

15 Aug '23

sudoreplay - replay sudo session logs Before running this command add these lines to the end of the sudoers file $ sudo vim /etc/sudoers Defaults log_output Defaults!/usr/bin/sudoreplay !log_output Defaults!/sbin/reboot !log_output :wq! save and exit To list sessions run by user venus $ sudo sudoreplay -l user venus To list sessions run by user venus with a command containing the string vim $ sudo sudoreplay -l user venus command vim regards, T.Dhanasekar

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1D1C - mkinitrd
by Dhanasekar 14 Aug '23

14 Aug '23

mkinitrd - it is used to create an image file that is loaded into the RAM disk during the boot process syntax $ sudo mkinitrd [options] <initrd-image> <kernel-version> $ sudo apt install dracut-core To create a new image file $ sudo mkinitrd -f /boot/initrd.img-5.11.0-051100-generic 5.11.0-051100-generic To display verbose output during the creation of the image file $ sudo mkinitrd -v -f /boot/initrd.img-5.11.0-051100-generic 5.11.0-051100-generic regards, T.Dhanasekar

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1D1C - expr
by Dhanasekar 13 Aug '23

13 Aug '23

expr - evaluate expressions To add two numbers $ expr 11 + 5 To subtract two numbers $ expr 20 - 10 To divide two numbers $ expr 20 / 4 To divide two numbers and want to see the remainder $ expr 25 % 6 To multiply two numbers $ expr 6 \* 4 To find the length of a string $ expr length indianlinuxusergroupchennai To check the index of character x $ a=kanchilinuxusergroup $ b=`expr index $a x` $ echo $b To extract the substring $ a=indianlinuxusergroupchennai $ b=`expr substr $a 21 27` $ echo $b To get the index of a substring from a string $ expr substr indianlinuxusergroupchennai 21 27 To compare two expressions $ a=50 $ b=60 $ c=`expr $a = $b` $ echo $c To match the number of characters of two string $ expr linuxos : linux $ expr linuxos : linuxo regards, T.Dhanasekar

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1D1C - export
by Dhanasekar 12 Aug '23

12 Aug '23

export - It is used to mark variables and functions to be passed to child processes To display all exported variables $ export To view all exported variables on the current shell $ export -p The variable ‘community’ has been assigned the value ‘ilugc’ $ community=ilugc $ export community check with $ printenv community To export shell function $ name() { echo "ilugc"; } $ export -f name $ bash $ name regards, T.Dhanasekar

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1D1C - disown
by Dhanasekar 11 Aug '23

11 Aug '23

disown - it is used to remove jobs from the job table $ ping google.com ^Z To list all current jobs $ jobs -l To remove all jobs $ disown -a To remove specific jobs $ disown %1 To remove the last job on the job table $ disown To remove currently running jobs $ disown -r To keep jobs running after log out $ disown -h <job_ID> regards, T.Dhanasekar

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1D1C - declare
by Dhanasekar 10 Aug '23

10 Aug '23

declare - it is used to declare shell variables and functions, set their attributes and display their values To declare a variable $ declare var $ var=65 To display the options and attributes of each variable name $ declare -p To declare a variable with a string value of all capital letters $ declare -l strvar="WELCOME TO ILUGC" To declare a variable with a string value of all small letters $ declare -u strvar="welcome to ilugc" regards, T.Dhanasekar

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1D1C - pidstat
by Dhanasekar 09 Aug '23

09 Aug '23

pidstat - Report statistics for Linux tasks. To report statistics for Linux tasks $ pidstat To display statistics for specific process id $ pidstat -p <pid_number> To display only tasks whose command name includes the string comm $ pidstat -C apache2 $ pidstat -C mysql To report I/O statistics $ pidstat -d To display all activities horizontally on a single line $ pidstat -h To display the process command name and all its arguments $ pidstat -l To report page faults and memory usage $ pidstat -r To display statistics for threads associated with selected tasks $ pidstat -t To report CPU usage $ pidstat -u To Report task switching activity $ pidstat -w regards, T.Dhanasekar

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1D1C - ifstat
by Dhanasekar 08 Aug '23

08 Aug '23

ifstat - Report InterFace STATistics To display statistics for all interfaces $ ifstat To Enable monitoring of all interfaces found for which statistics are available $ ifstat -a To hide interface which counters are null $ ifstat -z To add timestamp at the beginning of each line $ ifstat -t To Wrap lines that are larger than the terminal width (implies -w). Wrapped lines are prefixed with a cycling letter to ease reading $ ifstat -W To report bandwidth in kbits/sec instead of kbytes/sec. $ ifstat -b To displays version and the compiled-in drivers $ ifstat -v regards, T.Dhanasekar

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1D1C - ionice
by Dhanasekar 07 Aug '23

07 Aug '23

ionice - set or get process I/O scheduling class and priority syntax $ ionice -c <scheduling class> -n <priority value> <options><command> To set process with PID 89 as an idle I/O process $ ionice -c 3 -p 89 To run bash program with highest priority. $ ionice -c 2 -n 0 bash To Print the class and priority of the processes with PID 89 and 91. $ ionice -p 89 91 $ ionice -p <PID1> <PID2> regards, T.Dhanasekar

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1D1C - exit
by Dhanasekar 06 Aug '23

06 Aug '23

exit - cause normal process termination To terminate out from root shell root@ilugc:~# exit exit To terminate the shell for the user $ exit regards, T.Dhanasekar

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