Escaping an equals sign in DOS batch string replacement command

Question

I need to replace some text in a JNLP file using a DOS batch file to tune it for the local machine.

The problem is that the search pattern contains an equals sign wh

Answer 1

The best solution is to download and install Cygwin or GNUWin32 but, if you're really limited to the standard command processor, it can get a little messy.

This is not the fastest method in the world but it's at least functional. This command file processes each line one character at a time, treating specially the case where you find the stanza you're looking for.

@echo off
set init=50M
set max=75M
setlocal enableextensions enabledelayedexpansion
for /f "tokens=* delims=" %%a in (agility.jnlp) do (
    set str1=%%a
    call :morph
    echo !str2!>>agility_new.jnlp
    echo !str2!
)
endlocal
goto :eof

:morph
    set str2=
:morph1
    if not "x!str1!"=="x" (
        if "!str1:~0,18!"=="initial-heap-size=" (
            set str2=!str2!initial-heap-size="!init!"
            set str1=!str1:~24!
            goto :morph1
        )
        if "!str1:~0,14!"=="max-heap-size=" (
            set str2=!str2!max-heap-size="!max!"
            set str1=!str1:~20!
            goto :morph1
        )
        set str2=!str2!!str1:~0,1!
        set str1=!str1:~1!
        goto :morph1
    )
    goto :eof

With the input file:

<j2se version="1.5" initial-heap-size="100M" max-heap-size="100M"/>
next line
===

you end up with:

<j2se version="1.5" initial-heap-size="50M" max-heap-size="75M"/>
next line
===

Answer 2

One cannot simply replace (a substring with) an equal-sign, without splitting up (for-statement with "delims==") or trimming…

But perhaps you could go for this simpler but more confusing approach, using the following statement in your for-loop:

set str=!str:"100M" max-heap-size="%min%M" max-heap-size!

It just combines the string to replace with what comes after instead of what comes before, avoiding any equal-sign replacements entirely.

Answer 3

Here's an alternative solution. If you can afford to download GNU tools, you can use sed:

C:\test>set a=200
C:\test>sed -i.bak "s/^\(.*initial-heap-size=\"\).*\( max.*\)/\1%a%\"\2/" file 

Answer 4

If you can pass the arguments as something else, such as double underscores, you can iterate through them and convert them to '=' in the batch file.

@rem Replace __ with = in batch files.
@rem This works around the lack of equals signs in args
@rem args contains full args string with substitutions in place

setlocal enabledelayedexpansion

:argloop
if "%~1" NEQ "" (

set str=%~1
set out=!str:__==!
set %~1=!out!
set args=!args!!out!

SHIFT
goto :argloop
)

@rem Can now run program on a line on its own with just %args%

Source: https://github.com/mlabbe/batchargs