piping findstr's output

Question

Windows command line, I want to search a file for all rows starting with:

# NNN "<file>.inc"

where NNN is a number and <file> any string.

I want to use findstr, because I cannot require that the users of the script install ack.

Here is the expression I came up with:

>findstr /r /c:"^# [0-9][0-9]* \"[a-zA-Z0-9_]*.inc" all_pre.txt

The file to search is all_pre.txt.

So far so good. Now I want to pipe that to another command, say for example more.

>findstr /r /c:"^# [0-9][0-9]* \"[a-zA-Z0-9]*.inc" all_pre.txt | more

The result of this is the same output as the previous command, but with the file name as prefix for every row (all_pre.txt).

Then comes:

FINDSTR: cannot open |
FINDSTR: cannot open more

Why doesn't the pipe work?

---

snip of the content of all_pre.txt

# 1 "main.ss"
# 7 "main.ss"
# 11 "main.ss"
# 52 "main.ss"
# 1 "Build_flags.inc"
# 7 "Build_flags.inc"
# 11 "Build_flags.inc"    
# 20 "Build_flags.inc"
# 45 "Build_flags.inc(function a called from b)"

---

EDIT: I need to escape the dot in the regex also. Not the issue, but worth to mention.

>findstr /r /c:"^# [0-9][0-9]* \"[a-zA-Z0-9_]*\.inc" all_pre.txt

---

EDIT after Frank Bollack:

>findstr /r /c:"^# [0-9][0-9]* \"[a-zA-Z0-9_]*\.inc.*" all_pre.txt | more

is not working, although (I think) it should look for the same string as before then any character any number of times. That must include the ", right?

Answer 1

You are missing a trailing \" in your search pattern.

findstr /r /c:"^# [0-9][0-9]* \"[a-zA-Z0-9]*.inc\"" all_pre.txt | more

The above works for me.

Edit:

findstr /r /c:"^# [0-9][0-9]* \"[a-zA-Z0-9]*\.inc.*\"" all_pre.txt | more

This updated search string will now match these lines from your example:

# 1 "Build_flags.inc"
# 7 "Build_flags.inc"
# 11 "Build_flags.inc"
# 20 "Build_flags.inc"
# 45 "Build_flags.inc(function a called from b)"

Edit:

To circumvent this "bug" in findstr, you can put your search into a batch file like this:

@findstr /r /c:"^# [0-9][0-9]* \"[a-zA-Z0-9_]*\.inc" %1

Name it something like myfindstr.bat and call it like that:

myfinsdtr all_pre.txt | more

You can now use the pipe and redirection operators as usual.

Hope that helps.

Answer 2

I can't really explain the why, but from my experience although findstr behaviour with fixed strings (e.g. /c:"some string") is exactly as desired, regular expressions are a different beast. I routinely use the fixed string search function like so to extract lines from CSV files:

C:\> findstr /C:"literal string" filename.csv >  output.csv

No issue there.

But using regular expressions (e.g. /R "^\"some string\"" ) appears to force the findstr output to console and can't be redirected via any means. I tried >, >>, 1> , 2> and all fail when using regular expressions. My workaround for this is to use findstr as the secondary command. In my case I did this:

C:\> type filename.csv | findstr /R "^\"some string\"" > output.csv

That worked for me without issue directly from a command line, with a very complex regular expression string. In my case I only had to escape the " for it to work. other characters such as , and . worked fine as literals in the expression without escaping.

I confirmed that the behaviour is the same on both windows 2008 and Windows 7.

EDIT: Another variant also apparently works:

C:\> findstr /R "^\"some string\"" < filename.csv > output.csv

it's the same principle as using type, but just using the command line itself to create the pipe.

Answer 3

If you use a regex with an even number of double quotes, it works perfectly. But your number of " characters is odd, redirection doesn't work. You can either complete your regex with the second quote (you can use range for this purpose: [\"\"]), or replace your quote character with the dot metacharacter.

It looks like a cmd.exe issue, findstr is not guilty.