Piping to findstr's input

Question

I have a text file with a list of macro names (one per line). My final goal is to get a print of how many times the macro's name appears in the files of the current directory.

The macro's names are in C:\temp\macros.txt.

type C:\temp\macros.txt in the command prompt prints the list alright.

Now I want to pipe that output to the standard input of findstr.

type C:\temp\macros.txt | findstr *.ss (ss is the file type where I am looking for the macro names).

This does not seem to work, I get no result (very fast, it does not seem to try at all). findstr <the first row of the macro list> *.ss does work.

I also tried findstr *.ss < c:\temp\macros.txt with no success.

Rattan

Answer 1

I think you're confusing a little how findstr works. It gets input (to find things in – not the things to look for) either as a file name (pattern) or from stdin, but the things you're looking for are always given on the command line as an argument to findstr.

findstr foo xyz.txt

finds the string foo in the file xyz.txt.

type meh.txt | findstr x

finds the string x in the output of the previous command (in this case the contents of the file meh.txt – a nice waste of the type command, much akin to common misuse of cat).

Since you're after the counts instead of the actual lines the macro names appear in, I'd suggest a different approach. This assumes that your file containing the macros lists them one per line:

for /f "delims=" %x in (macros.txt) do @(echo %x: & find /c "%x" *.ss)

The for loop iterates over the contents of your file, line-wise. It then proceeds to print the name you're searching for and executing find /c which actually counts matching lines.

Ingenuity

I see! Is there a way to check which parameter can be taken from a pipe? Your last command worked alright, although the output of find is very ugly. Thanks! – Rattan

Well, you can can iterate manually (with for) over all *.ss files and throw find /c at them, parse its output and format it yourself. And well, most of the time it's pretty obvious what a program accepts as pipeline input since that path is usually used for large amounts of data which are otherwise read from a file. I have yet to see a program (PowerShell cmdlets don't count) that accepts arbitrary arguments also from the pipeline. – Ingenuity