Command Line Basics

Terminal vs shell

The shell interprets your commands (cmd, PowerShell, Bash). The terminal is the window that hosts it. Windows Terminal can host any of them in tabs, including a WSL distribution. The classic console window works too, with fewer features.

Same task, three shells

Task	Command Prompt	PowerShell	Bash
Where am I?	cd	Get-Location (pwd)	pwd
List files	dir	Get-ChildItem (ls, dir)	ls -l
Change folder	cd src	Set-Location src (cd)	cd src
Make folder	mkdir out	New-Item -ItemType Directory out (mkdir)	mkdir -p out
Create an empty file	type nul > f.txt	New-Item f.txt	touch f.txt
Copy / move / delete a file	copy, move, del	Copy-Item, Move-Item, Remove-Item	cp, mv, rm
Copy a folder with contents	xcopy src dst /e /i	Copy-Item src dst -Recurse	cp -r src dst
Delete a folder with contents	rmdir /s out	Remove-Item out -Recurse	rm -r out
Show a file	type f.txt	Get-Content f.txt	cat f.txt
Find text	findstr err f.txt	Select-String err f.txt	grep err f.txt
Count lines	find /c /v "" < f.txt	Get-Content f.txt | Measure-Object -Line	wc -l f.txt
List by size, largest first	dir /o-s	Get-ChildItem | Sort-Object Length -Descending	ls -lS
Help	help dir	Get-Help Get-ChildItem	man ls

PowerShell has short aliases such as ls and cat. They are not the Bash programs, so options like -la do not work there. Bash and Command Prompt pass text; PowerShell passes .NET objects. For large copies robocopy src dst /e is the more robust Windows tool. rmdir /s asks for confirmation unless you add /q.

To get a Bash shell on a Windows workstation, use Git Bash (installed with Git for Windows) or a WSL distribution.

Pipes and redirection

command > out.txt     # write output to a file (overwrite)
command >> out.txt    # append
command 2> err.txt    # send error output to a file
command1 | command2   # feed the output of one into the next

The same operators work in all three shells, but the commands on either side differ:

dir > out.txt
dir | findstr ".md"

Get-ChildItem > out.txt
Get-ChildItem | Where-Object Length -gt 1MB | Sort-Object Length

ls > out.txt
ls | grep ".md"

Shortcuts and cautions

• Press Tab to complete names, and the Up arrow (or Ctrl+R in Bash) for history.
• Quote paths that contain spaces with double quotes in all three shells: cd "C:\Program Files". In PowerShell, running a quoted program path needs the call operator: & "C:\Program Files\app\app.exe".
• Relative paths start from the current folder, absolute ones from the root. . is the current folder, .. its parent.
• Ctrl+C stops a running command.
• Check which program runs with where.exe git (cmd/PowerShell) or which git (Bash).
• Be careful with rm -r, rmdir /s and Remove-Item -Recurse: there is no recycle bin. Check where you are and list the folder first.

Try it

In each of the three shells, create a folder, add a file with text in it, search the file, list the folder sorted by size and delete everything again. Then redirect a directory listing into a file and count its lines.