¶ Basic Commands
echo - basically print
man - gives full manual page for any given command
cd - changes directory
ls - lists all files/directories in a directory (use -a to show hidden files)
cat - outputs contents of file to console
touch - creates files
su - changes user
ssh - allows for remote CLI access to other machines
scp - allows copying of files to remote machines
&& - executes a second command after the first has completed successfully
& - allows you to keep using commands while others are running (background the process)
$ - denotes an enviornment variable (export <varname>=<value> will set a variable)
| - pipes output to another command
; - like &&, but does not require first to run successfully
> - redirects output of command to a file
>> - appends output of a command to a file
chown <user>:<group> file - changes ownership of a file
chmod <ugo> file - sets read(4), write(2), and execute(1) permissions
rm - removes a file
mv - moves a file
mkdir/rmdir - makes and removes a directory, respectively
ln - creates a symbolic link between files
find - finds files
grep - searches within files for given input
sudo <command> - runs command with escalated permissions
adduser - adds user
userdel - deletes a user account
addgroup - adds group
delgroup - deletes a group
usermod -a -G <groups seperated by commas> <user> - modifies what groups a user is in
nc <ip> <port> - connect to ip address on given port
nc -lvnp <port> - start a listener on a given port
ping <ip> - check if a host is up using ICMP
curl <url> - access websites from terminal
wget <url> - download files
lsblk - lists block devices
lsusb - lists usb devices
lsof - lists opened files
lspci - lists pci devices
- Store bash commands in a file with a .sh extension
echo hello
echo whoami
whoami
- That file can be run using bash
<file>
> bash file.sh
hello
whoami
<user>
- You don't have to put a .sh if you use a shebang at the top of the file
#!/bin/bash
echo hello
echo whoami
whoami
¶ Important Files and Directories
/etc/passwd -> stores user information, shows all users on a system/etc/shadow -> stores all of the passwords (hashed, obviously)/tmp -> every file inside will get deleted upon shutdown/etc/sudoers -> controls sudo permissions of every user on system/home -> where all of your stuff is/root -> root user's home directory/usr -> where all software is installed/bin and /sbin -> contains basic programs for linux to function/var -> linux's home for misfit data$PATH -> contains all of the binaries you can execute