将 UFormat 应用于 System.DateTime 变量

Question

I am trying to apply a specific format to a DateTime variable on Powershell, but I am finding it impossible.

This works fine:

>> Get-Time -UFormat "%Y%m%d-%h%M%S"
20210412-135938

But if I try to assign it to a variable and then do the formatting, I encounter an error, for example

 $startDate=Get-Date -Year 2021 -Month 01 -Day 01 -Hour 11 -Minute 00 -Second 00
 $startDate=$startDate.addHours(10)
 $startDate=$startDate.addHours(23)
 ($startDate) -UFormat "%Y%m%d-%h%M%S"

Then I get an Token Uformat unexpected error. Could someone throw some light as on how to get this formatting to work?

Thank you,

Answer 1

You can pass an existing [datetime] value to Get-Date 's -Date parameter:

Get-Date -Date $startDate -UFormat "%Y%m%d-%h%M%S"

Answer 2

There are more ways of formatting a date that are more 'PowerShelly' then using UFormat:

1. use the.Net ToString() method:

(Get-Date).AddHours(10).ToString("yyyyMMdd-HHmmss")

2. use the -Format parameter of Get-Date :

$startDate = (Get-Date).AddHours(10)
Get-Date -Date $startDate -Format "yyyyMMdd-HHmmss"

3. or use the -f format operator:

'{0:yyyyMMdd-HHmmss}' -f (Get-Date).AddHours(10)

Answer 3

-UFormat switch belongs to the Get-Date commandlet. So you would use this syntax:

Get-Date ($startDate) -UFormat "%Y%m%d" for example.

And if I am interpreting what you "really" want in your date format string, you have incorrect case on the hour token.

"%Y%m%d-%h%M%S" Should be

Get-Date ($startDate) -UFormat %Y%m%d-%H%M%S

Which will return: 20210102-200000

These tokens - at least where I get them - are from TCL.

Goggle tcl clock manual page for a complete list.

I usually use -UFormat switch - I know TCL tokens and don't have to worry about escaping letters used in Microsoft date string tokens.

Get-Date ($startDate) -Format "Hello-yyyyMMdd-HHmmss-World"

returns: 20ello-20210102-200000-Worl2 because the H and d are tokens - and would need to be escaped \H \d

whereas

Get-Date ($startDate) -UFormat "Hello-%Y%m%d-%H%M%S-World"

returns: Hello-20210102-200000-World