How to check open ports on your Linux system

 

To check open ports on your Linux system you will need following package: nmap

Debian/Ubuntu got his package in standard repository already for ages.
Installing the nmap.

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To have simple check play with your local host IP, usually it’s 127.0.0.1.  To do so, type: nmap -sS -O 127.0.0.1

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In this example it’s clear which port are open:

22/tcp    open  ssh
139/tcp   open  netbios-ssn
445/tcp   open  microsoft-ds
3306/tcp  open  mysql
10000/tcp open  snet-sensor-mgmt

How to clean typed history in your Linux system

The information about what you typed is continuously stored in most Linux distributions. If it is BASH than it stored in .bash_history file in your current user folder.

The easiest way to delete the history is to type the following command:

history –c

All records from the file .bash_history  will disappear.

clean history in Linux

How to remove all useless file from /tmp folder in Linux.

There are many files could be stored in /tmp folder which are needed by running software on your Linux system. Removing them could cause you data loss.

However there is a safe way to do this.

Use the following command:

TMPTIME=0

This will remove all files from tmp folder.

However there is more elegant solution, but possible less stable. Use TMPFS for /tmp folder. That means that everytime you reboot, you get clean /tmp folder, as all file are stored in RAM of your system.

To see how setup TMPFS follow this link: TMPFS