linux command tips

Hi all, my second post on dev not an original post but i will describe here what's linux command i have used last week.

CTRL+r command

This command help me a lot. With this command i can search in my past command. very usfull when you always make the same command again and again.

!! command

I used this command to Replay the last command. Exemple : nano /var/log/syslog (error because non sudo)
Juste type sudo !! and the command open directly the syslog file.

|Echo$? command

With that i can see the return of the program

Cpu burn

If you want to test a program with full cpu

dd if=/dev/zero of=/dev/null

fullcpu() { dd if=/dev/zero of=/dev/null | dd if=/dev/zero of=/dev/null | dd if=/dev/zero of=/dev/null | dd if=/dev/zero of=/dev/null & }; fullcpu; read; killall dd

Number of open ssh connection

sudo netstat -tulpn | grep LISTEN