This is what I use in PowerShell 5.1:

(gc test.txt) | ForEach-Object {$_ -replace '^(.*)(\r?\n|$)', '^(.*)(\r?\n|$)', 'this is a repl $1\ntest tex $1 test$2'} | Set-Content test2.txt

This is test.txt:

ok
ok
ok

This is the current test2.txt:

this is a repl ok\ntest tex ok test

While it should be:

first ok
second ok third

I also tried this but got the following error:

sed -re "s|^(.*)(\r?\n|$)|this is a repl $1\ntest tex $1 test$2" test.txt > test2.txt

Error:

/usr/bin/sed: -e expression #1, char 19: unknown option to `s'

I also tried this (this works in Linux but not in Windows):

sed -e "s|^(.*)(\r?\n|$)|this is a repl $1\ntest tex $1 test$2" -i test.txt

/usr/bin/sed: -e expression #1, char 19: unknown option to `s'

How to find and replace regex?

I searched google and stackoverflow and tried some commands but they showed \n like above in my question.

CodePudding user response：

Inside single quotes in PowerShell, no string escape sequences are supported. '\n is a sequence of a literal \ followed with a literal n char.

You need to use double quotes and then use backtick n to insert a newline, i.e. "`n". So, use

"this is a repl `$1`ntest tex `$1 test`$2"