如何在PowerShell中的ACK中转义双引号和冒号

Question

I am using Ack version 2.04, in PowerShell. I want to search texts like "jsonClass":"Page" (quotes included) inside text files.

I can't seem to get the quoting and escaping correct.

ack -c --match '"jsonClass":"Page"'

It doesn't work in PowerShell. I guess ack's picking up the single quotes as well.

Escaping the double quotes gives an invalid regex error:

ack -c --match "\"jsonClass\":\"Page\""
  Invalid regex '\':
  Trailing \ in regex m/\/ at C:\CHOCOL~1\lib\ACK2~1.04\content\ack.pl line 315

I tried the literal option as well, but I think ack's interpreting the colon as file parameters.

ack -c -Q --match "jsonClass":"Page"
  ack.pl: :Page: No such file or directory

What am I missing?

I am using PowerShell v2.

Answer 1

To complement JPBlanc's effective answer with a PowerShell v3+ solution:

When invoking external programs such as ack , use of the so-called stop-parsing symbol, --% , makes PowerShell pass the remaining arguments through as-is , with the exception of expanding cmd.exe -style environment-variable references such as %PATH% :

ack --% -c --match "\"jsonClass\":\"Page\""

This allows you to focus on the escaping rules of the target program only , without worrying about the complex interplay with PowerShell's own parsing and escaping.

Thus, in PowerShell v3 or higher, the OP's own 2nd solution attempt would have worked by passing --% as the first parameter.

SeeGet-Help about_Parsing .

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Note that the exact equivalent of the above command without the use of --% (that also works in PSv2 and is generally helpful if you want to include PowerShell-expanded variables / expressions in other arguments ) would look like this:

ack -c --match '"\"jsonClass\":\"Page\""'

That is, the entire argument to be passed as-is is enclosed in single quotes , which ensures that PowerShell doesn't interpret it.

^{Note the inner enclosing " that aren't present in JPBlanc's answer (as of this writing). They guarantee that the argument is ultimately seen as a single argument by ack , even if it contains whitespace.}

Answer 2

If ack is a function it could happen that -c is interpreted by PowerShell. Can you test the following?

ack '-c' '--match' '"jsonClass":"Page"'

-c --match should be interpreted as --match is the value of parameter c in function ask .

If it's an EXE file, try:

ack -c --match '\"jsonClass\":\"Page\"'

Answer 3

In Powershell you can always use ' quote to handle inner " without problems.

But if you need to use " for a string (to interpolate a variable, for instance), you can escape them with `

$myvar = 'test'
$formatted = "{`"value`":`"$myvar`"}"

Write-Host $formatted
# output: {"value":"test"}