System inspection
Commands like uname, hostname and date help administrators identify Linux versions, server names and environment details.
Linux · Basic Commands
Linux · Lesson 3
Basic Commands
Daily use Solaris terminal commands for system administrators. File operations, navigation and system information commands. Difference between Linux and Solaris behavior. Practical production examples.
Goal of this lesson
Before working with Linux users, services, networking or shell scripting, you must first become comfortable with the Linux terminal and essential command-line tools.
In this lesson, you will learn how to inspect Linux system information, move between directories, read files and check storage usage using safe beginner-friendly commands.
These commands are the foundation for almost every Linux administration and DevOps task you will perform later.
Core command-line concepts
Filesystem navigation
Commands such as pwd, ls and cd allow you to safely move through Linux directories and inspect files.
Terminal productivity
Utilities like which, tty and bc improve command-line efficiency, troubleshooting and scripting workflows.
Step-by-step Linux command practice
The following examples demonstrate a realistic Linux terminal workflow. Practice every command carefully and observe how the shell prompt and command outputs change.
1. Check Linux system information
Use uname to identify the Linux kernel version, hostname and hardware platform.
terminal — bash
linux-lab[root@linux ~]# uname -a
Linux linux 5.15.0-91-generic #101-Ubuntu SMP x86_64 GNU/Linux
[root@linux ~]# uname -r
5.15.0-91-generic
2. Display the current working directory
pwd shows the exact directory your current terminal session is using.
terminal — bash
linux-lab[root@linux ~]# pwd
/root
[root@linux ~]# cd /var/log
[root@linux /var/log]# pwd
/var/log
3. Check system date and time
Use the date command to verify current server time and timezone settings.
terminal — bash
linux-lab[root@linux ~]# date
Wed Jan 10 14:23:45 IST 2024
4. List files and directories
The ls command displays files and folders inside the current directory.
terminal — bash
linux-lab[root@linux ~]# ls
backup.sh scripts notes.txt
[root@linux ~]# ls -lh
total 24K
-rwxr-xr-x 1 root root 2.1K Jan 10 11:15 backup.sh
-rw-r--r-- 1 root root 1.2K Jan 10 11:20 notes.txt
drwxr-xr-x 2 root root 4.0K Jan 10 11:18 scripts
5. Navigate between directories
Use cd to move through the Linux filesystem hierarchy safely.
terminal — bash
linux-lab[root@linux ~]# cd /etc
[root@linux /etc]# pwd
/etc
[root@linux /etc]# cd ..
[root@linux /]#
6. Display file contents
The cat command quickly displays text files directly inside the terminal.
terminal — bash
linux-lab[root@linux ~]# cat /etc/os-release
NAME="Ubuntu"
VERSION="22.04 LTS (Jammy Jellyfish)"
7. Check filesystem disk usage
df -h displays mounted filesystems and available disk space in human-readable format.
terminal — bash
linux-lab[root@linux ~]# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/sda2 50G 6.2G 41G 14% /
tmpfs 1.9G 0 1.9G 0% /run/user/0
8. Use the command-line calculator
bc provides simple arithmetic operations directly from the terminal.
terminal — bash
linux-lab[root@linux ~]# bc
10+25
35
quit
9. Locate executable command paths
which identifies the binary that will execute when a command is entered.
terminal — bash
linux-lab[root@linux ~]# which ls
/usr/bin/ls
[root@linux ~]# which bash
/usr/bin/bash
10. Identify the current terminal session
tty displays the pseudo-terminal device attached to the active session.
terminal — bash
linux-lab[root@linux ~]# tty
/dev/pts/0
11. Display or change the hostname
The hostname command identifies the Linux server on a network.
terminal — bash
linux-lab[root@linux ~]# hostname
linux
[root@linux ~]# hostnamectl set-hostname server1
[root@linux ~]# hostname
server1
Important command categories
Instead of memorizing commands randomly, it is better to group them by purpose. Most Linux commands fit into one of the following categories.
System information
Commands such as uname, date and hostname help identify kernel versions, time settings and server identity.
Navigation and file listing
Commands like pwd, ls and cd are used for navigating directories and viewing filesystem contents.
Viewing file contents
Commands such as cat, more, less and tail help administrators inspect configuration files and logs safely.
Getting help
The man command provides built-in Linux documentation and usage details for most commands.
Good command-line habits
Safe administration practices
- Verify your current directory before modifying files or running scripts.
- Use pwd and ls frequently to avoid accidental changes.
- Read command outputs carefully instead of blindly executing commands.
Learning and troubleshooting
- Use man pages regularly to understand command syntax and options.
- Practice commands repeatedly inside your Linux lab environment.
- Focus on understanding command behavior instead of memorizing outputs.
Important commands covered in this lesson
System and session information
- uname -a → display complete Linux kernel information
- uname -r → display Linux kernel release version
- whoami → display currently logged-in user
- date → display current date and system time
Navigation commands
- pwd → show current working directory
- ls → list files and directories
- cd /path → move to another directory
- cd .. → move one level upward
Viewing file contents
- cat /etc/os-release → display Linux distribution information
- more /var/log/syslog → read logs page by page
- less /var/log/syslog → navigate large files easily
- tail -f /var/log/syslog → monitor logs in real time
Processes and storage
- df -h → display filesystem disk usage
- du -sh * → display folder sizes
- ps -ef → display complete process list
- ps -ef | head → display only top process entries
Practice tasks for your Linux lab
- Log in to your Linux virtual machine and execute every command shown in this lesson.
- Record the outputs of
uname -a,df -handps -ef | headto better understand your Linux environment. - Use the
mancommand for at least three commands, such asman ls,man dfandman ps. - Practice moving between directories and reading files until terminal navigation feels comfortable and natural.
In the next lesson, you will build on these commands while learning Linux user and group management.