What is a .ps1 file?

About the format

A .ps1 file is a PowerShell script — text commands for Windows' modern automation shell, which can do essentially anything on the system: manage services and scheduled tasks, edit the registry, call Windows APIs, download and run code. Unlike .bat files, double-clicking a .ps1 does NOT run it — it opens in Notepad, a deliberate safety default backed by execution policy (which blocks unsigned scripts in most configurations until a user or admin loosens it). That makes casual double-click infection rare; instead, malicious PowerShell almost always arrives launched by something else — a shortcut, a macro, a .bat wrapper — often as an encoded one-liner (powershell -enc <base64>) precisely so there's no readable .ps1 on disk. For scripts you receive legitimately: read them (they're text), be suspicious of Invoke-Expression on downloaded strings and of long base64 blobs, and run them from an elevated PowerShell only when you understand what they change.

How to open a .ps1 file

Is a .ps1 file dangerous?

Yes when executed — full system automation. The double-click default (opens in Notepad) is your friend; keep it.

Related file types