String.TrimStart() doesn't function as I expected, why?

Question

I've got the command below:

> "D:\abc\abcName".TrimStart("D:\abc")
Name

In fact I wish this to trim exactly "D:\abc" and return only "abcName" but seems that the 2nd "abc" is trimmed off as well.

Why does this happen and how can I fix it?

I'm using PS 4.0.

Answer 1

The argument to TrimStart() is treated as an array of chars, not a literal string. All consecutive characters at the start of the string that match any of the characters inside the argument "D:\abc" is removed.

You could use the -replace operator instead, which takes a regex pattern as its right-hand argument:

PS C:\> "D:\abc\abcName" -replace "^D:\\abc\\"
abcName

---

If you are unsure which characters to escape (such as \), let the [regex] class do it for you:

PS C:\> "D:\abc\abcName" -replace "^$([regex]::Escape("D:\abc\"))"
abcName

Answer 2

Mathias R. Jessen points it out.

Looks like you want to get the filename from a path. Instead of using TrimStart consider use the static GetFileNameWithoutExtension method:

[system.io.path]::GetFileNameWithoutExtension("D:\abc\abcName.bat")

Result:

abcName

Or if you want the complete filename with extension:

[system.io.path]::GetFileName("D:\abc\abcName.bat")

Result:

abcName.bat