Unable to escape pipe character (|) in powershell

问题

I am trying to find number of pipe(|) characters in each line of a file. I am using following command to do so.

gc .\test.txt | % { ($_ | select-string "|" -all).matches | measure | select count }

Its not counting the pipe symbol.

I also tried

1. `|
2. '|'
3.  |

Can anyone tell me how to escape pipe character in power shell?

If i am using strings or characters other than pipe the command is working properly.

回答1:

A backslash \ is the escape character for a regular expression.

gc .\test.txt | % { ($_ | select-string "\|" -all).matches | measure | select count }

If you're unsure, you can always use [RegEx]::Escape():

$pattern = [RegEx]::Escape("|")
gc .\test.txt | % { ($_ | select-string $pattern -all).matches | measure | select count }

The pipe otherwise does not have to be escaped in PowerShell inside a string.

回答2:

Use the -SimpleMatch parameter for Select-String, which turns off regular expression matching.

来源：https://stackoverflow.com/questions/34231674/unable-to-escape-pipe-character-in-powershell