ورقة مرجعية: Bash مقابل PowerShell

Written Explanation

Why they look so different

Bash comes from the Unix tradition: short command names (ls, cp, rm), options with dashes (-l, -r), and text flowing through pipes. PowerShell was designed by Microsoft with longer Verb-Noun names (Get-ChildItem, Copy-Item), named parameters (-Recurse), and objects flowing through pipes. Microsoft's documentation states that PowerShell pipelines pass objects from one command to the next.

Both are useful. Bash is the default language of most servers. PowerShell is the default of Windows and runs on macOS and Linux too.

The phrasebook

The table covers each job from this module. The PowerShell column gives the full command first and common aliases in brackets, when they exist on your system.

Redirection and pipes look the same in both shells. What flows through is different (text versus objects), but the symbols are the same, which makes them an easy bridge.

Aliases: why ls works in PowerShell

An alias is a short nickname for a command. PowerShell ships with aliases that look like Unix commands, so ls, cd, cat, cp, and mv often work there. Microsoft's Remove-Item page lists the aliases del, erase, rd, and ri on all platforms, plus rm and rmdir on Windows.

Two traps follow:

• An alias is not the real Bash command. ls -l may fail in PowerShell, because -l is a Bash option and PowerShell's Get-ChildItem does not have it. The alias name is borrowed, but the options are PowerShell's.
• Aliases vary between systems. The Microsoft page says rm is an alias only on Windows. On PowerShell for Linux or macOS the real rm program is available instead. Learn the full names for anything you save in a script.

Finding an equivalent yourself

You do not need to memorize everything. Use the shell to ask:

• PowerShell: Get-Alias ls shows what a nickname points to. Get-Command *item* lists commands with item in their name. Get-Help Copy-Item explains one.
• Bash: type ls or which ls shows what a command is (output differs between systems), and man ls or ls --help explains it.
• Search engine rule: search for the shell and the job, such as "powershell list files sorted by size". Include the shell's name, or the results will mix both worlds.

PowerShell's Verb-Noun pattern helps. If you know the verb you want (Get, Set, New, Remove, Copy, Move), tab completion after the dash shows the nouns.

Syntax differences to remember

Microsoft's pipeline page confirms that a line ending in | continues the pipeline on the next line, and PowerShell 7 also accepts a pipe at the start of the next line. The PATH separators and case-sensitivity rules are confirmed on Microsoft's environment-variables page.

Do not mix them in one session

A shell understands one language. If you type a Bash command in PowerShell, or the reverse, you get an error that mentions the command not being recognised or found:

PS> export NAME=value
export : The term 'export' is not recognized as the name of a cmdlet...
$ Get-ChildItem
bash: Get-ChildItem: command not found

The wording varies with version. The remedy is to look at the prompt, decide which shell you are in, and use that shell's words. Some people run Bash tools inside PowerShell on Windows (through Git Bash or WSL) and are comfortable switching. For a beginner, one shell at a time is simpler.

Which one should you pick?

Pick the shell your computer provides by default (PowerShell on Windows, Bash or zsh on macOS and Linux), and learn the other's most common commands later using this page. If your career moves toward servers, expect Bash. If it moves toward Windows tooling, PowerShell will appear more often. Learning both at a basic level is a normal outcome.