- ILUG-D - lists.fsci.in

1D1C - ipset
by Dhanasekar 05 Aug '23

05 Aug '23

ipset is used to set up, maintain and inspect so called IP sets in the Linux kernel To create ip set called hacker_ips $ sudo ipset -N hacker_ips iphash To add IP address to the hacker_ips ipset $ sudo ipset -A hacker_ips 172.122.150.22 $ sudo ipset -A hacker_ips 192.168.100.22 To drop all ip address stored in ipset called hacker_ips $ iptables -A INPUT -m set --set hacker_ips src -j DROP To create ipset named my_blacklist $ sudo ipset create my_blacklist hash:ip hashsize 4096 To drop all ip address stored in ipset called my_blacklist $ sudo iptables -A INPUT -m set --set my_blacklist src -j DROP To add IP address in ipset my_blacklist $ sudo ipset add my_blacklist 192.168.100.22 $ sudo ipset add my_blacklist 172.122.150.22 $ sudo ipset add my_blacklist 192.168.100.10/24 To make ipset persistent across reboots $ sudo ipset save > /etc/ipset.conf To view the sets $ sudo ipset -L To delete a set named hacker_blacklist $ sudo ipset -X hacker_blacklist To delete all sets $ sudo ipset destroy regards, T.Dhanasekar

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1D1C - updatedb
by Dhanasekar 04 Aug '23

04 Aug '23

updatedb - update a database for plocate To refresh database content for locate command $ sudo updatedb To print paths of files as they are found $ sudo updatedb --verbose regards, T.Dhanasekar

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1D1C - ipcalc
by Dhanasekar 04 Aug '23

04 Aug '23

ipcalc - An IPv4 Netmask/broadcast/etc calculator To calculate subnet for 192.168.122.10/16 $ ipcalc 192.168.122.10/16 To calculate subnet for 192.168.122.10/16 without display ANSI color codes $ ipcalc -n 192.168.122.10/16 To Suppress the bitwise output $ ipcalc -b 192.168.122.10/16 To Deaggregate address range $ ipcalc -r 192.168.122.1 192.168.122.101 $ ipcalc -r 10.10.0.1 10.10.1.1 $ ipcalc -r 172.122.150.10 172.155.150.20 regards, T.Dhanasekar

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1D1C - sipcalc
by Dhanasekar 03 Aug '23

03 Aug '23

sipcalc - IP subnet calculator To calculate subnets for 192.168.122.1/24 $ sipcalc 192.168.122.1/24 To calculate subnets for 192.168.122.1/16 $ sipcalc -i 192.168.122.1/16 regards, T.Dhanasekar

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1D1C - enable
by Dhanasekar 02 Aug '23

02 Aug '23

enable command is used to enable or disable the shell built-in commands. To list the shell builtin commands which are enabled $ enable To disable the shell builtin command alias $ enable -n alias check the list with $ enable $ alias c=clear To make the alias command to enable again $ enable alias $ alias c=clear $ c To disable pwd command $ enable -n pwd check with $ enable $ pwd To enable the pwd command again $ enable pwd $ pwd To disable history command $ enable -n history check with $ enable $ history To enable the history command $ enable history $ history regards, T.Dhanasekar

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1D1C - dnsdomainname
by Dhanasekar 01 Aug '23

01 Aug '23

dnsdomainname - show the system's DNS domain name To display the alias name $ dnsdomainname -a To display all the fully qualified domain names $ dnsdomainname -A To set default hostname if none available $ dnsdomainname -b ilugc To Displays the short hostname $ dnsdomainname -s To display addresses for the host name $ dnsdomainname -i To display all addresses for the host $ dnsdomainname -I To Displays the Network Information System (NIS) domain name $ dnsdomainname -y regards, T.Dhanasekar

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1D1C - mpstat
by Dhanasekar 31 Jul '23

31 Jul '23

mpstat - Report processors related statistics To report the processor stats $ mpstat 5 10 To report all processor stats $ mpstat -A 5 10 To get the processor number for which the stats are displaying $ mpstat -P 3 10 To display statistics for processor one (0) and processor two (1), and update at an interval of 2 seconds $ mpstat -P 0,1 3 To get the version info $ mpstat -V To report the CPU utilization stats $ mpstat -u 3 10 regards, T.Dhanasekar

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1D1C - mkhomedir_helper
by Dhanasekar 30 Jul '23

30 Jul '23

mkhomedir_helper - Helper binary that creates home directories To make user home folder after account creation $ sudo mkhomedir_helper <username> $ sudo mkhomedir_helper ilugc regards, T.Dhanasekar

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1D1C - nologin
by Dhanasekar 29 Jul '23

29 Jul '23

nologin - politely refuse a login First check nologin exists in /etc/shells $ cat /etc/shells if nologin is not found then append # echo "/usr/sbin/nologin" >> /etc/shells To set a user’s shell to nologin # usermod <username> -s /sbin/nologin # usermod ilugc -s /sbin/nologin regards, T.Dhanasekar

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1D1C - rename
by Dhanasekar 28 Jul '23

28 Jul '23

rename - renames multiple files $ touch a.jpg b.jpg c.jpg d.jpg $ ls a.jpg b.jpg c.jpg d.jpg To change .jpg to png $ rename -v 's/jpg/png/' *.jpg To change above files to uppercase $ rename 'y/a-z/A-Z/' *.png To change above upper case files to lowercase $ rename 'y/A-Z/a-z/' *.PNG regards, T.Dhanasekar

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