Writing to a file in batch - batch-file

Question

I've set up an app for a couple of friends and me in batch with a auto-updating system, but I need to add a line of code in the auto-updating system. I decided to completely rewrite the file, it takes a long time to add 'echo' in from to every line and, '>>text.txt' at the end of every line and added '^' when needed, so I was wondering if there was an easier way of writing lot's of code to a file in batch.
Example:
#echo off
rem I need a way to do the following without adding 'echo' and '>>text.txt'
echo echo Checking for updates... >text.txt
echo echo 1.4 ^>^>new.txt >>text.txt
echo ping localhost -n 2 ^>nul >>text.txt
rem and so on and so on.
Or if there is a way to simply add a new line of code in a specific place in the file, that would also help!
Thanks in advance!

Answer 1

The following is how you can more easily and efficiently do what your current code does, by removing all of those individual write processes.
#( Echo #Echo Checking for updates...
Echo #(Echo 1.4^)^>^>"new.txt"
Echo #(%__AppDir__%ping.exe LocalHost -n 2^)^>NUL
)>"text.txt"
There are other possibilities, but at this time, based on the lack of information in your question, I'm reluctant to expand further at this time.

Answer 2

If I understand correctly, then you could do the following:
in the batch file, prepend each line of text that you want to output with :::: (this constitutes an invalid label that is going to be ignored);
then use the following code:
rem // Redirect to file:
> "text.txt" (
rem // Find all lines that begin with `::::` and loop over them:
for /F "delims=" %%T in ('findstr "^::::" "%~f0"') do (
rem // Store currently iterated line:
set "TEXT=%%T"
rem // Toggle delayed expansion to avoid loss of `!`:
setlocal EnableDelayedExpansion
rem // Remove `::::` prefix and output remaining line:
echo(!TEXT:*::::=!
endlocal
)
)
replace set "TEXT=%%T" by call set "TEXT=%%T" if you want to enable percent expansion within the returned text (so it could, for example, contain %~nx0, which would then be expanded to the file name of the script).
I am using this technique a lot (without the output redirection) for help systems in my batch files (/?).

Answer 3

Your asked
I need a way to do the following without adding echo and >>text.txt
The script takes advantage of the line continuation character, the caret ^.
The first character after the caret ^ is always escaped, so do linefeed characters:
#echo off
SETLOCAL EnableDelayedExpansion
call :init
>text.txt (
echo #echo off%NL%
Checking for updates...%NL%
>^>new.txt echo 1.4%NL%
>NUL ping localhost -n 2
)
ENDLOCAL
exit /b
:init
( set LF=^
%= 0X0D FORM FEED =%
)
::0X0A Carriage Return
FOR /F %%a in ('copy /Z "%~f0" nul') do set "CR=%%a"
::Create newline/line continuation character
set ^"NL=^^^%LF%%LF%^%LF%%LF%^^" %= Unix-Style Endings \n =%
::set ^"NL=%CR%^^^%LF%%LF%^%LF%%LF%^^" %= Windows-Style Endings \r\n =%
exit /b
The variable %LF% is a escaped linefeed, and %NL% is a escaped %LF% plus a escaped caret ^ for line continuation.
The code
>^>new.txt echo 1.4%NL%
>NUL ping localhost -n 2
might seem strange. Why isn't the first caret ^ escaped?
Because %NL% already escaped it.
Sources:
Explain how Windows batch newline variable hack works
https://stackoverflow.com/a/5642300/12861751
https://www.dostips.com/forum/viewtopic.php?t=6369