Search for a string recursively
grep -rnw './' -e "imsearchingyou"
only specific files:
grep -rnw './' --include=".php" -e "imsearchingyou"
or a bit more clearly:
grep -Hornw './' -e "imsearchingyou"
Edit the default version of an alternatives software
update-alternatives --set php /usr/bin/php5.6
Generate super secure passwords
apt install pwgen
pwgen -s -y 32 -N 1
Checking opened ports
apt install nmap
nmap -p 80 test.de
for upd ports:
nmap -sU -p 53 test.de
for localhost:
netstat -tulpn
Add user
sudo adduser --system --shell /bin/bash --group --disabled-password --home /home/anton anton
Add user without login shell
useradd -s /sbin/nologin anton
Add user to group
usermod -a -G groupName anton