CLI Tools Cheat Sheet

A cheat sheet for useful Linux CLI tools

awk

• A tool with similar capabilities to cat and cut where it can read file contents and customize the output.

// Selecting text fields from a file
root@box ~ $ awk '{print $1 ""}' subdomains.txt
blog.techwithtyler.dev
braindump.techwithtyler.dev
techwithtyler.dev
www.techwithtyler.dev

cat

• A tool for reading file contents onto standard output (STDOUT).

// Reading files
root@box ~ $ cat subdomains.txt
blog.techwithtyler.dev 234234234
braindump.techwithtyler.dev 25346536
techwithtyler.dev 43564356743
www.techwithtyler.dev 45776568

cut

• A tool for removing sections from each line of files

// Selecting text fields from a file
root@box ~ $ cut -f2 -d " " subdomains.txt
234234234
25346536
43564356743
45776568

// Another option, piping output to cut
root@box ~ $ cat subdomains.txt | cut -f2 -d " "
234234234
25346536
43564356743
45776568

export

• Useful to create env vars or updating your $PATH

# adds a tool to your path
export PATH=$PATH:/opt/aws/bin

find

• More advanced than the locate tool.

• It can search based on several attributes e.g., permissions, timestamp, file size, and more.

// Finding a file

$ find -name my-*
./a/b/c/d/e/f/g/my-lost-file

// Finding files owned by root where all users have 'write' permissions

$ find / -type f -group root -perm -a=w 2>/dev/null
/proc/sys/kernel/ns_last_pid
/proc/pressure/io
/proc/pressure/cpu
[SNIP]

locate

• A useful tool for quickly finding files and directories.

• Install it with: sudo apt install mlocate

• It's a local database that gets updated regularly with a cron job but can otherwise be forced to update with: sudo updatedb

// Finding a file

$ locate my-lost-file
/home/parrot/a/b/c/d/e/f/g/my-lost-file

which

• Searches the $PATH environment variable for any executable matching the search.

// Checking if python3 is installed 

$ which python3
/usr/bin/python3