Sometimes you need a very fast overview over a current Linux system. In this case, the next commands can be very helpful.
With the following commands, you get information about the kernel.
dmesg | grep Linux
Under Redhat you can use this command.
rpm -q kernel
Find release information on Debian systems
and under Redhat systems use
In the following config files, you can read system wide environmental variables about the user’s shells.
sudo cat /etc/profile
sudo cat /etc/bash.bashrc
In your home directory, environmental variables are set as well.
In the file “bashrc” contains commands, aliases and functions from user’s bash.
This file is read and executed every time a login shell exits.
env is a shell command for Unix and Unix-like operating systems. The command “env” is used to print a list of environment variables.
The command “set” shows the system variables with the corresponding contents.
Print all processes with the owner’s user name.
The command “top” display Linux processes.
The following commands list all installed applications.
ls -alh /usr/bin/
ls -alh /sbin/
Lists all jobs form the current user’s scheduler.
This command gives a detailed view for all defined jobs.
ls -al /etc/cron*
Linux – information gathering (part 1)
Linux – information gathering (part 2)
Linux – information gathering (part 3)
Thx @Programming Wolf