Built-In Command Line Tools

Your terminal will have several commands already built into the command line. Below are a few of them with examples of how they are used.

pwd: print working directory (where am I currently?)

 

/: root directory (folder that holds all other folders)
./: current directory (current folder)
../: parent directory (folder containing your current folder)

 

ls: list directory contents (list everything in current folder) (usage)

• Flags:

  • -l: long format (permissions, sizes, dates, etc.)

  • -F: indicate item types

    • trailing / = directory

    • @ = link

    • * = executable

  • -r: reverse order (reverse alphabetic order)

 

mkdir: make directory (i.e. folder) (usage)

 

mv: move object (usage)

• mv [source(s)] [destination]

• *Warning* Will overwrite object if name already exists

• When in the same folder: renames object

• Flags:

  • -i: interactive (ask for confirmation before overwriting)

 

cp: copy object (usage)

• cp [source object(s)] [destination]

• *Warning* Will overwrite object if name already exists

• Flags:

  • -R: copy directory (i.e. folder)

  • -i: interactive (ask for confirmation before overwriting)

 

head: display the beginning (i.e. top) of a file (usage)

• Flags:

  • -1: display first row

  • -3: display first 3 rows

 

tail: display the end (i.e. bottom) of a file (usage)

• Flags:

  • -1: display last row

  • -3: display last 3 rows

 

| (shift + backslash): pipe (use outputs from one command as inputs for another)

• Example: display the 10th row of a file

  • head -10 path/to/file | tail -1

 

wc: word count (lines, words, characters) (usage)

• Flags:

  • -l: lines

  • -w: words

  • -c: characters