🫐 Commands
CLI

CLI

Basics

  • ctrl + u deletes line
  • alt + click move cursor in line
  • ctrl + a move to beginning of line
  • ctrl + e move to end of line
  • ctrl + l or clear clears screen
  • ctrl + d or exit exit terminal

Shell

  • man commandName info on command man find
  • whatis commandName simplified info on command
  • whereis executableName returns path to executable whereis pyton3
  • whoami shows username
  • exit exit a shell session

Navigation

  • pwd present working directory
  • pwd -P current full directory path
  • ls list shows files in current directory
  • ls -a shows all files, including secret
  • ls -l shows long format info on files in current directory file permissions, user, the group the user belongs too, the date of creation
  • cd navigates to the home directory
  • cd /path/to/directory change directory
  • cd .. navigates up one level in the directory tree

File Commands

  • > redirect output to file(copy)
  • >> append output onto file
  • < read input from a file
  • | piping, use the output from left side program as input for right side program

Open files

  • open file\ name.txt opens ‘file name.txt’ ‘\ ‘ allows for a space
  • open file* opens all files beginning with ‘file’ eg. file.txt or file243.js * is a wildcard
  • open file? opens all files beginning with ‘file’ and ending in one wild card. eg. file2 of fileA
  • open -a /Applications/AppName.app open file with application
  • open -a ‘Google Chrome’ websiteAddress open file in browser
  • open pwd`` opens 'present working directory'
  • open . open current folder
  • code . opens directory in VSCode

Create, move, and delete files

  • mkdir directoryName creates a directory/folder
  • mkdir .directoryName creates a secret directory/folder
  • mkdir -p directoryName/nestedDirectoryName creates nested directory
  • touch fileName.html creates file
  • touch filename{1,2,3,4}.html creates 4 filename.html files
  • touch filename{1..4}.html creates 4 filename.html files
  • touch .secretFile.html creates hidden file
  • cp copiedFile.txt pastedFile.text copies a file
  • cp -Rv copiedDirectory pastedDirectory copies a directory
  • rm fileName.text deletes file
  • rm * deletes all files in directory
  • rmdir directoryName deletes directory
  • rm -rf directoryName deletes directory and everything inside it
  • mv path/oldName.txt path/newName.txt renames a file or directory

Read files

  • head filename outputs the first 10 lines of a file
  • tail filename outputs the last 10 lines of a file
  • cat filename displays file content in cli
  • cat file* displays files with names starting with file
  • cat < - adding < before filename allows you to access files named with special chars
  • cat “filename w spaces” adding quotation marks allows you to access files with spaces in the name
  • cat ./* all files in folder (allows you to find files that begin with special chars
  • cat file1 file2 displays multiple files content in cli
  • cat file1 file2 > newcombinedfile creates a new combined file
  • cat < file1 > file2 copies file1 to file2
  • cat filename | fmt -w 20 fmt—format. -w width. Display file content with width of 20 chars
  • cat -n filename prints line numbers

Find, sort, and search files

  • find . -name src -type d find directory with name src
  • find . -path '*/folderName/*.py' -type f find all of type files that have a in a folder
  • du fileName -c estimate file size in bytes
  • sort filename sorts lines of a file alphabetically
  • sort filename | uniq -c sort lines, output duplicate lines only once, -c will count lines
  • sort filename | uniq -u return only unique lines
  • wc filename outputs how many lines, words, and characters are in a file
  • grep pattern filename looks for text inside files. eg. grep admin /desktop/folder
  • grep -B 0 -A 5 'searchWord' filename return the line with the search word and x lines before (-B) and x lines after
  • grep -C 2 foo README.txt return the line and the same amount of lines before and after
  • grep -f file1 file2 compares and returns similar lines
  • grep "YOUR SEARCH STRING" filename > output-file copies (> means redirect) grep results into output-file
  • grep -i pattern filename ignores word case
  • grep -r pattern filename searches all files under the specified directory
  • egrep ‘condition’ filename (grep -E) output lines containing condition. eg. egrep ‘practice|PRACTICE’ filename returns all lines containing the word practice
  • fgrep ‘condition’ filename (grep -F) find the exact string ‘condition’ in file

Compare, rename, and manipulate files

  • ls -v | cat -n | while read n f; do mv -n "$f" "$n.ext"; done renames all files in directory with incrementing numbers
  • diff file1 file2 compares differences between files
  • sed -n 5p file print one line of file
  • sed ‘word’ file removes the word from file
  • sed '7d;10d;11d' file1.txt > file2.txt removes multiple lines from file, results to file2

Compress and download files

  • file filename return file type
  • gzip filename.txt compress file
  • gzcat filename allows you to view a compressed file without unzipping it
  • gunzip filename.gzdecompress file (must be a .gz)
  • tar -xvf filenamedecompresses tar file
  • bzip2 -d filename.bz2decompressed bzip2 file (must be a bz2)
  • wget file downloads file

Processes

  • Top real time view of CPU usage and processes
  • ps process - any instance of a program, each process has a unique process id
  • ps -ef list all processes
  • lsof -i tcp:3000 checks what is running/listening on port
  • kill -15 PID TERM the process at process id
  • kill -3 PID QUIT the process at process id
  • killall processName ends all processes with name

DNS/IP

HTTP request

⭐curl stands for client URL
  • -H headers
  • -X request
  • -d data
  curl -H "X-Internal-Challenge: secret-key" -H "Content-Type: application/json" -X POST http://localhost:3000/ -d '{"payload"{"url":"https://demo.appwrite.io/","method":"GET","headers":{"x-client-version":"1.0.0"},"body":""}}'

Unix file permissions

  • chown change owner
  • chown -options userName:groupName filename
  • chmod change mode, allows users to change the read, write, and execute permissions for files and folders
  • ls -l filename view info returns permissions
symbolfiletypemode
-filerread4
ddirectorywwrite2
ilinkxexecute1

Example: -rw-r--r--@ - regular filetype, rw- user can read and write, r— groups and others can only read

Types of users:

  • User Person who has created the file.
  • Group Group of other users who share similar privileges as that of the owner.
  • Others Other members who have access to the path where you have kept the files.

Permission level options:

  • 4 Read Permission
  • 2 Write Permission
  • 1 Execute Permission
  • 0 No permission

Calculated (user read + user write + user execute)(group read + group write…)(others…)

# full permission for all
chmod 777 filename.txt
# USER: 4+2+1 = 7 GROUP: 4+2 = 6 OTHERS: 0
# USER: read, write, execute GROUP: read, write OTHERS: none.
chmod 760 filename.txt

Resources

✨Git + GitHub