Syntax for specific RegEx in command line FINDSTR call

Question

I am writing a batch script that takes in various arguments before starting another process. In the example below I am checking the case where the first argument was 1, and the second argument is in the form of "any number of digits 0-9, followed by the letter k, m, or g" (I am specifying the amount of memory the process should start with i.e. 10g = 10 Gb memory).

If I just want a number this will suffice:

IF [%1] EQU [1] ECHO %2|findstr /r "[^0-9]" > nul
IF [%1] EQU [1] IF errorlevel 1 echo starting test number %1 with %2 of memory

What I thought would be an obvious segway to add the letters k, m, or g led me to this (I've tried with and without the '*'):

IF [%1] EQU [1] ECHO %2|findstr /r "[^0-9]*[kmg]" > nul
IF [%1] EQU [1] IF errorlevel 1 echo starting test number %1 with %2 of memory

However I have been unable to match any string to this FINDSTR pattern. Basically I am looking for a FINDSTR that matches [0-9][0-9]*[kmg]. I am fairly certain I am close but am having trouble working out the correct syntax.

dbenham · Accepted Answer · 2012-12-18 15:49:56Z

2

Even the first code you posted does not work. [^0-9] looks for any non-digit. I think you wanted ^[0-9], which means any string that starts with a digit. Your logic is also wrong: FINDSTR sets errorlevel to 0 if found, and 1 if not found. I prefer to use the conditional && and || operators to test the result instead of IF.

I recommend the following for what you are attempting. I've thrown in the /I switch to make it case insensitive. I add the /X switch to prevent the string from matching if there are extra characters before or after the number with suffix.

@echo off
if "%~1" equ "1" echo(%~2|findstr /rix "[0-9][0-9]*[kgm]" >nul && (
  echo starting test number %~1 with %~2 of memory
)

Unfortunately, FINDSTR does not support the ? meta-character. So the solution is slightly more complicated if the suffix is optional (if you want to support bytes, kilobytes, megabytes, and gigabytes). You would need to search for either of 2 strings, one with the suffix, and one without. FINDSTR breaks the search string into multiple search strings at spaces.

@echo off
if "%~1" equ "1" echo(%~2|findstr /rix "[0-9][0-9]*[kgm] [0-9][0-9]*" >nul && (
  echo starting test number %~1 with %~2 of memory
)

answered Dec 18, 2012 at 15:49

dbenham

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David Ruhmann Over a year ago

Reference for those interested in && and || robvanderwoude.com/condexec.php

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