Objects vs. Text

The PowerShell Paradigm Shift

The single most important concept to grasp when moving from a Linux shell to PowerShell is the difference in what commands output. This fundamental change affects how you filter, process, and automate tasks.

In Traditional Shells (like Bash)

Commands in shells like Bash primarily output streams of unstructured text. When you run ls -l, you get back a multi-line string of characters formatted for human eyes. To use this data programmatically, you must “parse” that text using other tools like grep, awk, or sed to extract the information you need, often by relying on column numbers or regular expressions. This can be powerful, but it’s often complex and fragile.

In PowerShell

Cmdlets (PowerShell commands) output structured .NET objects. When you run Get-ChildItem (the equivalent of ls), you don’t get back text; you get a collection of FileInfo and DirectoryInfo objects. Each object is a container of data with well-defined properties.

• .Name: The file or directory name.
• .Length: The size of the file in bytes.
• .LastWriteTime: The date and time the file was last modified.
• .IsReadOnly: A true/false value indicating if the file is read-only.
• …and many more.

You can access these properties directly without parsing any text.

A Practical Example

Let’s say you want to get the names of all files in the current directory that are larger than 20 kilobytes.

The Bash Approach

# We have to parse the text output of ls -l.
# We check if column 5 (size) is greater than 20480, then print column 9 (name).
# This is fragile; it breaks if the output of ls -l ever changes.
ls -l | awk '$5 > 20480 {print $9}'

The PowerShell Approach

# We get file objects and filter them based on a property.
# This is robust because it uses named properties, not text positions.
Get-ChildItem | Where-Object { $_.Length -gt 20KB } | Select-Object Name

Why It Matters

• No More Fragile Parsing: You no longer need to rely on text manipulation for everyday tasks.
• Discoverability: You can easily inspect an object to see all of its available properties and methods using the Get-Member cmdlet.
• Rich Pipeline: The pipeline becomes much more powerful, as you can pass rich, structured data between commands instead of just text.