History

Unix was first released in 11/3/1971.

What is Unix

Stands for UnipleXed Information Computing System.

• Unix is an operating system.

All MacOS derivatives are Unix certified.

• Compliance required to use the UNIX trademark.

What is a Shell

Shell is a macro processor that executes commands.

alias

alias is a shortcut for a command.

# clearing the alias
alias ll='ls -la'

# when command has a quote, prefer function over `alias`
somefn() {
  echo "Hello, World!"
}

List

# List contents of current directory
ls

# List ALL contents of current directory

## in default ls-style
ls -a

## in vertical list style
ls -la

## OR
la

Search

Command line utility for searching plain-text data sets for lines that match a regex

grep

Rename OR Move (mv)

Rename

Change file's old_file_name to new_file_name in current directory

• Also works for directory names
  • You should use gmv when you are inside of a git repository or Git will lose track of the changes (especially in directory with submodules)

mv old_file_name new_file_name

Move

When moving a directory, mv command also works

mv dir_name new_location/dir_name

Name with Spaces

Escape out the spaces with the \ escape character before the special character

# Moving "Learning Python Programming - Working Files"
mv Learning\ Python\ Programming\ -\ Working\ Files

Copy

Copy the contents of a file or the output of a command to the system clipboard

# copying the contents of a file
pbcopy < file.txt

# copying the output of a command
ls -l | pbcopy

Dot Command

Every directory in Unix-like OS contains (as a minimum), an object represented by a single dot and another represented by a double dot.

Single dot (.) represents the directory itself and the double dot (..) refers to its parent directory.

These dots are created in every directory.