Command Line


  • cmd-k - clear entire terminal
  • ctrl-a - beginning of line
  • ctrl-e - end of line
  • man <command> - manual for most commands (man page)
  • --help - after most commands to see its options
  • "space" - delimiter between executable arguments
  • "something in quotes" - sends it as a single argument, so there can be spaces
  • \" " - escapes the space so it will still be a single argument
  • echo - echos a command back to the shell (you can use it with wildcards to preview what you will get from your pattern match before potentially doing something destructive)
  • -flag or --flag following a command they allow you to change a commands standard behavior, can be a single letter or a word
  • history - shows list of recent commands
  • atom . mate . - opens current directory in Atom or Textmate respectively
  • each user has their own permissions that determine what they are allowed to do
    • whoami - tells you who the current user is
    • root user is the top-level user --- they can create and delete other users
    • usually don't lof in as root user --- you use the command sudo (superuser do) --- allows you to use root user commands without compromising your system's security
  • source path_to_file - executing the file, can use after updating a file without restarting your terminal


  • ~/- home directory
  • / - root directory
  • .. - parent directory
  • . - current directory
  • cd somedir - change to "somedir" directory
  • cd - - change to the previous directory
  • mkdir - make directory
  • mkdir -p - will create a new path/tree of multiple directories
  • rmdir - removes directory, but not a tree...must use rm -r for that
  • pwd - print working directory


  • ls - list files
  • ls -l - list files long
  • ls -al - list files all, long
  • ls -G - will highlight the directories in a color to separate them from files
  • cat - print contents of a file
  • head & tail - print the first or last lines of a file
  • head -n 5 - prints first 5 lines --- same thing can be done with tail
  • touch existing_file_name.txt - updates the file's modified date
  • touch new_file_name.txt - makes new file
  • wc file_name - get lines, words, characters, file name (with spaces separating them) --- can do multiple files
  • wc -l - number of lines
  • rm - remove ( trash, etc that can be undone)
  • rm -i - prompts you before deleting each file
  • rm -f - doesn't prompt you before deleting a write-protected file, does not display an error if the specified file doesn't exist
  • rm -r/rm -R - permits recursive removal of directories and their contents
  • stat -x file_name - prints file info

Copying and Moving

  • cp source destination - copies a file from the source location to the destination location --- the source file must exist, but the destination doesn't, a file with the name you give it will be created --- be careful, if you use an existing destination name it overwrites whatever is there
  • cp file1 file2 destination_directory - copy multiple files
  • cp -R - copy directory and its contents (-R means recursively)
  • mv source destination - moves a file/directory to the destination location


Cut and Paste

  • cut -d, -f1 file - -d is for a delimiter and , is the delimiter --- -f is for a field and 1is the field you want, can select multiple fields
  • paste - pastes lines from multiple files together --- concatenates the same line numbers into one line


  • date - makes the Unix system time pretty and readable
  • date -r file_name - gives you the last modification date of the file
  • ln -s source symbolic_link - creates a symlink between a source file/directory and the linked file/directory
  • ls -l symbolic_link verifies the link was created
  • to overwrite the destination path of the symlink, use the -f (--force) option
  • to overwrite a symlink us -f (force) option ln -sf my_file.txt my_link.txt otherwise will get an error
  • unlink symlink_to_remove
  • rm symlink_to_remove
    • when removing (or un-linking) a symbolic link not append the / trailing slash at the end of its name
    • if you delete or move the source file to a different location, the symbolic file will be left dangling (broken) and should be removed


  • chmod - stands for 'change mode' - it's the command to change access permissions of file system objects (files and directories) --- for more info:



  • ls d?g - lists files that match the pattern d-any single character-g --- the ? is a wildcard
  • ls d*g - lists files that match the pattern d-any number of characters-g --- the * is the wildcard --- can use wildcards with any other commands (ls, cp, mv, etc.)


  • grep pattern file - returns line/s with matches...can use with wildcards, regular expressions, to find partial matches, with spaces, etc. --- grep is case sensitive
  • grep -i - ignores case
  • grep -o - to only print the words that match your pattern
  • grep -c - gives the number of matching lines
  • grep -c -v - gives number of lines that don't match --- can do with one dash as well -cv

Standard Input/Output and Pipes

  • > file_name - redirects standard output from terminal to file
  • < filename - redirects a file to standard in
  • paste <[echo hello) <[echo world), paste <[cut -d, -f3 file_name) <[cut -d, -f1 file_name) - executes the right first and sends it to stdin --- second example lets you switch columns 1 and 3 which you can't do with cut alone
  • | - pipe operator - connect stdout to stdin --- can string more than 2 commands together --- can concatenate 2 files --- can pipe to sort

Command Line Editors


  • vim file_name - opens file in vim or create the file in your directory if it doesn't exist
  • starts in command mode which lets you issue command and do things like copy and paste (but not type)
  • i - to get in insert(edit) mode
    • must be in insert mode to make changes (type)
  • esc - to exit insert mode
  • / to search
  • : - to enter last line mode
  • wq - to write (save) and quit
  • q, or x - to quit
  • "Vim is a powerful text editor that has hundreds of commands."


  • less file_name ` opens file in less
  • / - to search
  • q - to quit


  • easier to use than vim and less!!!
  • nano file_name.txt - takes you into the nano text editor with that file open
  • shows common commands at bottom of the screen
  • ctrl-w - search
  • ctrl-k - cut line
  • ctrl-u - uncut line (paste)
  • ctrl-o - will ask you for the file output name
  • crtl-c - cancel

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