Commands summary

Unix architecture and file system

Unix Command	Acronym translation	Description
who or whoami	-	Tells you who the current user is. The 'who' command is not present in MobaXterm but you can use 'whoami' instead
man <COMMAND>	Manual	A very useful command. By using this command on other Unix commands, it gives you a manual of how to use them. This command is not present in MobaXterm, but you can instead use google to find command manuals.
cal [OPTION]	Calendar	Gives you the current date in a calendar form
date [OPTION]	-	Gives you the current date
pwd [OPTION]	Print working directory	Where are you? Shows the current directory
ls [OPTION] [DIRECTORY]	List segments	Shows the files in the current directory if a filepath is not given.
cd [OPTION] <DIRECTORY>	Change Directory	Moves you to a specified directory. You can type 'cd ..' to move one directory back. The '..' simply means to go up one level towards your root
mkdir [OPTION] <DIRECTORY>	Make directory	Makes the specified directory
rmdir [OPTION] <DIRECTORY>	Remove directory	Removes the specified directory if it's empty. To remove a non-empty directory, one can use the recursive option 'r.
ln [OPTION] <DIRECTORY> <LINK_NAME>	Link	Can be used to create links (shortcuts) between files and directories.

Standard streams and working with files

Unix Command	Acronym translation	Description
touch [OPTION] <FILE>	-	Touches a file. If the file doesn't exist already it will create a file with the specified name. If it already exists it will update the date of the file
mv [OPTION] <FILE> <destination directory or another filename>	Move	Moves a file to a specified directory. It can also be used to rename files.
rm [OPTION] <FILE>	Remove	Removes specified file in current directory. This command can also be used to remove non-empty directories.
cp [OPTION] <FILE> <destination directory or another file>	Copy	Works a lot like mv, but moves a copy of the file instead. Can also be used copy the content of one file to another file.
cat [OPTION] <FILE>	Concatenate	Concatenates files and displays it in standard output. If used on one file, the content of that file is displayed in the command line interface.
head [OPTION] <FILE>	-	Outputs the first part of a file
tail [OPTION] <FILE>	-	Outputs the last part of a file
less <FILE>	-	Shows a screenfull of the file. This is a useful command for viewing big files as it loads at smalls segments at a time. q --> quit , space --> scroll forward one page , b --> scroll backward one page. Arrow keys can be used to scroll up and down one line at a time.
wc [OPTION] <FILE>	Word count	Counts the lines and words in the file/files, but can also count other things based on the options you give it.
paste [OPTION] <FILE>	-	Merges lines from different files.
cut [OPTION] <FILE>	-	Removes different parts of a file depending on on what is specified in the option.
echo [OPTION] <STRING>	-	Outputs the string to your command line interface. In computer language, a string is just a sequence of characters.
wget [OPTION] <URL>	web get	A non-interactive network downloader used to download files located at the URL.
curl [OPTION] <URL>	client URL	Similarly to wget, it is used to download files at the specified URL. This is an alternative MAC OS users, where wget doesn't work.
tee [OPTION] <FILE>	It's named after the 'T-splitter' used in plumbing.	Splits output so that it can be outputted to both the terminal and a file.

Text editors and some shell scripting

Unix Command	Acronym translation	Description
alias <alias_name>=<The stuff you want to make an alias for>	-	Creates an alias called alias_name for what you've inserted on the right side of '='
source <FILE>	-	Executes the contents of a file in current shell. Changes made when the file is run will be permanent until changed. It is synonymous with Prompt$ . <FILE>.
bash <FILE>	Bourne again shell	Bash will execute <FILE> as a different process. This way, changes that occur while the file is being executed cannot affect your shell.

Setting up your shell script

Unix Command	Acronym translation	Description
which <COMMAND>	-	Shows the full path to the command.
read [OPTION] [input1] [input2] [input3]	-	Can be used to prompt user for input and save them as variables [input1]..[input3].

Filtering and regular expressions

Unix Command	Acronym translation	Description
grep [PATTERN] <FILE>	Global regular expression print.	Uses regular expressions select lines in a file that matches the pattern.
sed [OPTION] <SCRIPT> <FILE>	stream editor	Allows user to edit files without actually opening the files using regular expressions.
tr [OPTION] <SET1> <SET2>	Translate	Translates characters from the standard input and writes to the standard output.
sort [OPTION] <FILE>	-	Sorts the content of a file.

File permissions

Unix Command	Acronym translation	Description
chmod [OPTION] [MODE] <FILE>	Change mode.	Changes file permissions on a file according to the mode given. No need to be confused about [MODE], as it just another term used for file permission. It can be specified with letters or numbers. It's easier to understand what you're doing with letters but using numbers can be faster. In the example, we'll show how to use both.
chown [OPTION] [OWNER][:[GROUP]] <FILE>	Change owner.	Change file owner and/or group. This can be done separately or simultaneously by typing [OWNER]:[GROUP].
chgrp [OPTION] <FILE>	Change group.	Change group of a file.

File compression and advanced packaging tools

Unix Command	Acronym translation	Description
tar [OPTION] <ARCHIVE> <FILES>	Tape archive	Archive utility tool, used to create and extract archives. Archives are simply multiple files that have been combined into one file.
gzip [OPTION] <FILE>	GNU Zone informational Protocol.	Compresses <FILE>
gunzip [OPTION] <FILE>	GNU un Zone informational Protocol.	Decompresses <FILE>
zip [OPTION] <FILE>	Zone informational Protocol	Archive and compression utility. Used to make an archive or compress <FILE>.
unzip	un Zone informational Protocol	Decompresses <FILE>
apt [OPTION] <PACKAGE>	Advanced Packaging tool	Package manager for Ubuntu with many utilities.

Processes: foreground and background, ps, top, kill, screen, nohup and daemons

Unix Command	Acronym translation	Description
<COMMAND> &	-	Runs command as a background process
bg %<PID>	bg and PID are short for background and process identification respectively	Continues a stopped job in the background
fg %<PID>	fg and PID are short for foreground and process identification	Continues a stopped job in the foreground
sleep <NUMBER>[s/m/h/d]	-	Delays for a specified amount of time. This can be specified <NUMBER> and suffixes; s, m, h and d which are short seconds, minuted, hours and days respectively. By default, the suffix is s
top [OPTION]	-	Displays all the processes running on your computer
ps [OPTION]	Process status	Reports a snapshot of current processes
kill [OPTION] <PID>	-	Sends a signal to a process and by default this signal is to terminate the process
screen [OPTION]	-	Used to create new terminal windows that are detached from each other. Child processes created within these new terminal windows are not affected if their parent process is terminated
disown	-	Dissociates process from current terminal session
nohup [OPTION]	No hangup	Used to run commands immune to hangups, ignoring stdin. By default output is redirected to nohup.out.
pstree	Process tree	Display a tree of parent and child processes

Understanding network and remote servers: IP/URL, ssh, scp, wget, curl

Unix Command	Acronym translation	Description
wget [OPTION] <URL>	web get	A non-interactive network downloader used to download files located at the URL.
curl [OPTION] <URL>	Client url	Similarly to wget, it is used to download files at the specified URL. This is an alternative MAC OS users, where wget doesn't work.
ssh <PORT> <user@IP/Domain_name>	Secure shell	Used to establish a secure connection to a remote server/system. It's also known as secure shell protocol.
scp <PORT> <user@IP/Domain_name> <user@IP/Domain_name>	Secure copy protocol	Starts a secure copy protocol, which copies files securely across from remote networks to clients or from clients to remote networks.
telnet <URL> <PORT>	Teletype network	Establishes a connection with the specified URL and port.
ifconfig [OPTION]	Interface configuration	Displays currently active networks but when used with a, it displays the status of all networks.
nslookup	Name server lookup	Used to obtain information about a server through a DNS (Domain name system) server.
ping [OPTION] <IP/URL>	Packet Internet Groper	Checks network connectivity between host (your computer) and host/server.