​du command is very simple and useful for Summarize and estimate files, directories space usage on Linux or Unix system. Can get different types of disk usage information. Also show usage of each FILE, recursively for directories.

SCP command help us copies files, directories between hosts on network. If you could not found command we need to install openssl client package.

By default Linux operating system use more RAM memory for disk cache, because of reading data from cache if more faster than reading data from hard drive, we can clear cached on your system and this is a non-destruction operation,

If you want to be merge two line set to one, SED and AWK command can use for this.

We have already discussed about find and replace a line or specific word in simple commands using SED.

If you are using Dedicated server or Virtual private server, files or directories access,modify,changes,logs reports time based on your timezone settings.

Linux-Unix operating systems is logged system activities some one place. This post describe about how to get know last logged and log out, shutdown time, system reboot time from the logs. This information stored in wtmp and btmp file.