# terminal

## Open a terminal from another (e.g. VSCode) terminal

```bash
open -a terminal .
```

## Add to path on Mac

```bash
vim /etc/paths
```

## Using pipe and grep

```bash
pip3 freeze | grep Xlsx
```

## Open current directory in finder

```bash
open .
```

## Find and kill process on a port

```bash
lsof -i tcp:3000
kill [PID]
```

## Recursively remove `node_modules`

```bash
find . -name "node_modules" -exec rm -rf '{}' +
```

## Location of a command in PATH

The following will return something along the lines of `hie is /Users/username/.local/bin/hie`:

```bash
type -a hie
```

## Common commands

* `clear` - clear the terminal
* `pwd` - print working directory
* `mkdir` - make directory
* `touch` - create a file (e.g. touch example.txt)
* `cp` - copy (e.g. cp file.txt target\_directory)
* `mv` - move (e.g. mv file.txt target\_directory), can also rename a file (e.g. mv old\_file\_name.txt new\_file\_name.txt)
* `rm` - remove (e.g. rm file.txt), can also remove files recursively (e.g. rm directory\_name)
* `echo` - send to stdout
* `cat` - read content of a file
* `alias` - set aliases (e.g. alias pd="pwd" means pd can be used interchangably with pwd)
* `export` - set environment variables!
* `env` - return list of environment variables
* `>` - redirect stdout to a file (e.g. echo "Hello" > hello.txt)
* `>>` - append stdout to a file
* `<` - redirct stdin to a command (e.g. cat < file.txt)
* `|` - pipe stdout of LHS as stdin to RHS
* `wc` - word count (of a text file)
* `uniq` - unique the contents of a file (on a line-wise basis?)
* `grep` - global regular expression print (-i adds case insensitivity, -R recursive, e.g. within directory)
* `sed` - 'streams editor', can be used for find and replace
* `nano` - text editor
* `source` - source \~/.bash\_profile makes all aliases available in the current session
* `history` - command history

## Environment settings

* Stored in:

```bash
~/.bash_profile
```

(where \~ is an alias for $HOME and . represents a hidden file)

## How cmd line works

* Most commands are stored in `/bin`
* `/bin` is a directory on the path (...and hence is available in a terminal session)
* Hence you can see all commands using: `cd /bin`, `ls`