New to Linux or support hundreds of servers? Here are my top-10 favorite linux commands/one liners.

  • df -h - defacto for seeing how much drive space is per file system, used, available, percentage, and where it is mounted.

    ➜  ~ df -h
Filesystem             Size  Used Avail Use% Mounted on
udev                   6.8G     0  6.8G   0% /dev
tmpfs                  1.4G  2.2M  1.4G   1% /run
/dev/mapper/data-root  450G  157G  271G  37% /
tmpfs                  6.9G  173M  6.7G   3% /dev/shm
tmpfs                  5.0M     0  5.0M   0% /run/lock
tmpfs                  6.9G     0  6.9G   0% /sys/fs/cgroup
/dev/nvme0n1p2         4.0G  2.1G  2.0G  52% /recovery
/dev/nvme0n1p1         498M  187M  311M  38% /boot/efi
tmpfs                  1.4G   20K  1.4G   1% /run/user/110
tmpfs                  1.4G   96K  1.4G   1% /run/user/1000
/dev/sda1              916G   45G  825G   6% /media/bryanlurer/1tb_ssd

  • sysinfo - Well this one is a script for me.. GITHUB LINK HIER. I just type sysinfo and it gives me the details I need.

    ➜  ~ sysinfo
Username: bryanlurer
Hostname: a300
External IP: 123.456.789.12
Weather: San Miguel, Philippines: ⛈ +32°C
Load:  1.34 0.51 0.42 1/1397 21739

  • curl v2.wttr.in - Weather in your terminal! Lots of formatting options for one liner, such as in the sysinfo command.

  • apti - Ubuntu/Debian - An alias for the following: sudo apt update -y ; sudo apt install -y

  • yumi - RHEL/CentOS/Amazon Linux - An alias for the following: sudo yum update -y ; sudo yum install -y

  • wavemon - If you have wifi it will show signal, link quality, signal over time, which frequency you are using. A fantastic CLI tool for Linux.

  • ssh user@host(name or IP) - connects to host as user

  • ssh -p <port> user@host(name or IP) - connects to host on specified port as specified user

  • ssh-copy-id user@host - adds your ssh key to host for passwordless login - should be standard!

  • passwd - Change your password

  • date - Shows the current date and time.

    [ec2-user@ip-172-26-6-216 ~]$ date
Sun Jul 19 02:15:21 UTC 2020

  • uptime - Shows system uptime and load average.

    [ec2-user@ip-172-26-6-216 ~]$ uptime
02:14:34 up 2 min,  2 users,  load average: 0.04, 0.04, 0.01

  • w - Displays who is logged in, duration, and ip

    [ec2-user@ip-172-26-6-216 ~]$ w
02:13:26 up 0 min,  2 users,  load average: 0.15, 0.06, 0.02
USER     TTY      FROM              LOGIN@   IDLE   JCPU   PCPU WHAT
ec2-user pts/0    vps-722c62c5.vps 02:12   30.00s  0.00s  0.00s -bash
ec2-user pts/1    1.2.3.4   02:13    1.00s  0.00s  0.00s w

  • uname -a - Shows kernel information

    [ec2-user@ip-172-26-6-216 ~]$ uname -a
Linux ip-172-26-6-216 4.14.181-108.257.amzn1.x86_64 #1 SMP Wed May 27 02:43:03 UTC 2020 x86_64 x86_64 x86_64 GNU/Linux

  • man {command} - Shows the manual for specified command.

    [ec2-user@ip-172-26-6-216 ~]$ man ls
...
LS(1)                                                                         User Commands                                                                        LS(1)

NAME
   ls - list directory contents

SYNOPSIS
   ls [OPTION]... [FILE]...

DESCRIPTION
   List information about the FILEs (the current directory by default).  Sort entries alphabetically if none of -cftuvSUX nor --sort is specified.

  • du -h {file/dir} - Shows the disk usage of the files and directories.

    [ec2-user@ip-172-26-6-216 ~]$ du -h
8.0K	./.ssh
668M	.

  • ps -u {user} - lists your processes

    [ec2-user@ip-172-26-6-216 ~]$ ps -u ec2-user
PID TTY          TIME CMD
2800 ?        00:00:00 sshd
2801 pts/0    00:00:00 bash
2830 ?        00:00:00 sshd
2831 pts/1    00:00:00 bash
2887 pts/1    00:00:00 ps

  • curl - Transfers data.

    [ec2-user@ip-172-26-6-216 ~]$ curl -s ifconfig.me
52.52.52.52

  • wc -l - Counts lines in a file:

    [ec2-user@ip-172-26-6-216 ~]$ wc -l important_data.txt 
71721955 important_data.txt

  • ping {host/ip} - Pings host and outputs results. Will continue forever unless -c {#} is provided.

    [ec2-user@ip-172-26-6-216 ~]$ ping 1.1.1.1 -c 5
PING 1.1.1.1 (1.1.1.1) 56(84) bytes of data.
64 bytes from 1.1.1.1: icmp_seq=1 ttl=49 time=1.18 ms
64 bytes from 1.1.1.1: icmp_seq=2 ttl=49 time=1.23 ms
64 bytes from 1.1.1.1: icmp_seq=3 ttl=49 time=1.23 ms
64 bytes from 1.1.1.1: icmp_seq=4 ttl=49 time=1.21 ms
64 bytes from 1.1.1.1: icmp_seq=5 ttl=49 time=1.23 ms

--- 1.1.1.1 ping statistics ---
5 packets transmitted, 5 received, 0% packet loss, time 4005ms
rtt min/avg/max/mdev = 1.183/1.219/1.234/0.036 ms

And that is it for now. What commands are your favorites and most useful?