Linux CLI Tools(continually update)

This page only lists some commonly used commands and their options, for more details, please check man command or use the official docs! apropos is another command you should master to search in man I highly recommend you to read The Art of Command Line

Special Notes

• the = in shell scripts is to set value of variable, = is conditional character

restart

sudo shutdown now -r

find

find [path...] [expression]

Expression may consist of: operators, options, tests, and actions.

stat

stat filename

free

df

lsblk

list blocks information in tree format

fdisk

It is an interactive tool, here are some commonly used commands:

• n - new a partition
• d - delete a partition
• l - list all available kinds of partition

mkfs

click tab to see what file systems are supported

mount

mount <device> <directory>

to enable mount automatically, you need to edit /etc/fstab (file systems table)

umount

umount <device>

ln

Chinese reference

ln f1 f2
ln -s f1 f2
ln -s /path/to/the/sourcefile /path/to/the/link

readlink

alias

alias alias_name='command [options]'
# example
alias ll='ls -alh' # pay attention to the charactors`'`

unalias

unalias <alias_name>

ftp

ftp -P <port> <ip_addr>
ftp> cd Downloads
ftp> put source_path_of_your_file

wget

curl

netstat

netstat -tulpn

ss

ss -tulpn

ps

ps -aux

top

htop

tar

tar xvf file.tar # Extracting files from Archive 
tar xvzf file.tar.gz # Extracting a gzip tar Archive
tar xvjf file.tar.bz2 # Extracting a bzip2 tar Archive

tar cvf file.tar *.cpp # Creating an Archive of all .cpp files
tar cvzf file.tar.gz *.cpp # Extracting a gzip tar Archive of all .cpp files
tar cvjf file.tar.bz2 *.cpp # Extracting a bzip2 tar Archive of all .cpp files

Packages Manager

apt

PPA(Personal Package Archive)

PPA (Personal Package Archive) is a term used in the context of Ubuntu and other Debian-based Linux distributions. It refers to a Personal Software Repository or Personal Package Archive created by individuals or groups to host and distribute software packages. PPAs allow developers and users to share, publish, and update software packages that may not be available in the official repositories of the distribution.

In the context of APT (Advanced Package Tool), you can use PPAs to add additional software sources for obtaining updated packages. Here are the general steps:

Add a PPA: Use the add-apt-repository command to add a PPA. You need to provide the address of the PPA after the command. For example:

sudo add-apt-repository ppa:example/ppa

Here, ppa:example/ppa is the actual address of the PPA. After running this command, the system will ask for confirmation to add the PPA, and you need to confirm.

GPG

apt-key list

dnf

pipx

Reference

nmtui

My personal understanding for the name is network manager terminal-ui

crontab

usage: crontab [-u user] [-n] file crontab [ -u user ] [ -i ] { -e | -l | -r }

• -h (displays this help message)
• -u user (choose the user whose crontab is touched)
• -e (edit user’s crontab) will let you specify a text-editor(Vim)
• -l (list user’s crontab)
• -r (delete user’s crontab)
• file (default operation is replace, per 1003.2)
• -n (dry run: checks the syntax, then bails out)

iptables

Firewall system will check the rules from top to bottom, and will end as soon as it match the one. If there isn’t matched rule, the firewall will execute following the default policy.

There are 5 kinds of data packages:

• PREROUTING
• INPUT
• OUTPUT
• FORWARD
• POSTROUTING

and there are 4 policies that can be implemented:

• ACCEPT
• REJECT (drop and respond)
• LOG
• DROP (drop and won’t respond)

examples:

iptables -I INPUT -s 192.168.10.0/24 -p tcp --dport 22 -j ACCEPT # accept all ssh request from 192.168.10.0/24