Shell

The shell is the thing that stares at you when you open up a terminal on your machine. It usually looks like

user@ntpl-lap-206 ~$

We type in commands and we get the output. A good shell environment, is configured for you, when you install the config files from neoito-hub.

Adding to $PATH

The $PATH variable stores the list locations where the shell looks for binaries. Do a $ which ls. The output should be /bin/ls. Do an $ echo $PATH on the terminal.

So, if we want to add binaries/executables in a particular folder (example: /home/akts/Programs/mongodb/bin), to the $PATH variable, execute

export PATH="$HOME/Programs/mongodb/bin:$PATH"

Environment Variables

To figure out what shell we're using, do a $ echo $SHELL. If we're running bash, the file to set environment variables will the $HOME/.bash_profile. For zsh, it'd be $HOME/.zprofile

Here's an excrept from a sample .bash_profile file.

export GOPATH="$HOME/go"
export GOROOT="$HOME/Programs/go"
export PATH="$PATH:$GOROOT/bin"

CLI Cheatsheet

System information

# Display Linux system information
uname -a
# Display kernel release information
uname -r
# Display Linux system information
uname -a
# Display kernel release information
uname -r
# Show all network interfaces
ip a

Monitoring

# Display and manage the top processes
top
# Interactive process viewer (top alternative) - sudo apt install htop
htop
# Capture and display all packets on interface eth0
tcpdump -i eth0
# Monitor all traffic on port 80 ( HTTP )
tcpdump -i eth0 'port 80'

User Management

# Add the akts account to the docker group
usermod -aG docker akts

File and directories

# List all files in a long listing (detailed) format
ls -al
# Display the present working directory
pwd
# Create a directory
mkdir directory
# Remove (delete) file
rm file
# Remove the directory and its contents recursively
rm -r directory
# Force removal of file without prompting for confirmation
rm -f file
# Forcefully remove directory recursively
rm -rf directory
# Copy file1 to file2
cp file1 file2
# Copy source_directory recursively to destination. If destination exists, copy source_directory into destination, otherwise create destination with the contents of source_directory.
cp -r source_directory destination
# Rename or move file1 to file2. If file2 is an existing directory, move file1 into directory file2
mv file1 file2
# Create symbolic link to linkname
ln -s /path/to/file linkname
# Create an empty file or update the access and modification times of file.
touch file
# View the contents of file
cat file
# Browse through a text file
less file
# Display the first 10 lines of file
head file
# Display the last 10 lines of file
tail file
# Display the last 10 lines of file and "follow" the file as it grows.
tail -f file

Process Management

# Display your currently running processes
ps
# Display all the currently running processes on the system.
ps -ef
# Display process information for processname
ps -ef | grep processname
# Display and manage the top processes
top
# Interactive process viewer (top alternative)
htop
# Kill process with process ID of pid
kill pid
# Kill all processes named processname
killall processname
# Start program in the background
program &
# Display stopped or background jobs
bg
# Brings the most recent background job to foreground
fg
# Brings job n to the foreground
fg n

Archiving

# Create tar named archive.tar containing directory.
tar cf archive.tar directory
# Extract the contents from archive.tar.
tar xf archive.tar
# Create a gzip compressed tar file name archive.tar.gz.
tar czf archive.tar.gz directory
# Extract a gzip compressed tar file.
tar xzf archive.tar.gz
# Create a tar file with bzip2 compression
tar cjf archive.tar.bz2 directory
# Extract a bzip2 compressed tar file.
tar xjf archive.tar.bz2

Installing packages

# Install software from source code.
tar zxvf sourcecode.tar.gz
cd sourcecode
./configure
make
make install
# For .deb files, use the dpkg tool with root privilleges
sudo dpkg -i file.deb

The above list is taken directly from lta.