Split long commands in multiple lines through Windows batch file

Question

How can I split long commands over multiple lines in a batch file?

Answer 1

You can break up long lines with the caret ^ as long as you remember that the caret and the newline following it are completely removed. So, if there should be a space where you're breaking the line, include a space. (More on that below.)

Example:

copy file1.txt file2.txt 

would be written as:

copy file1.txt^ file2.txt 

Answer 2

The rule for the caret is:

A caret at the line end, appends the next line, the first character of the appended line will be escaped.

You can use the caret multiple times, but the complete line must not exceed the maximum line length of ~8192 characters (Windows XP, Windows Vista, and Windows 7).

echo Test1 echo one ^ two ^ three ^ four^ * --- Output --- Test1 one two three four* echo Test2 echo one & echo two --- Output --- Test2 one two echo Test3 echo one & ^ echo two --- Output --- Test3 one two echo Test4 echo one ^ & echo two --- Output --- Test4 one & echo two 

To suppress the escaping of the next character you can use a redirection.

The redirection has to be just before the caret. But there exist one curiosity with redirection before the caret.

If you place a token at the caret the token is removed.

echo Test5 echo one <nul ^ & echo two --- Output --- Test5 one two echo Test6 echo one <nul ThisTokenIsLost^ & echo two --- Output --- Test6 one two 

And it is also possible to embed line feeds into the string:

setlocal EnableDelayedExpansion set text=This creates ^ a line feed echo Test7: %text% echo Test8: !text! --- Output --- Test7: This creates Test8: This creates a line feed 

The empty line is important for the success. This works only with delayed expansion, else the rest of the line is ignored after the line feed.

It works, because the caret at the line end ignores the next line feed and escapes the next character, even if the next character is also a line feed (carriage returns are always ignored in this phase).

Answer 3

You can break up long lines with the caret (^), just remember that the caret and the newline that follows it are removed entirely from the command, so if you put it where a space would be required (such as between parameters), be sure to include the space as well (either before the ^, or at the beginning of the next line — that latter choice may help make it clearer it's a continuation).

⚠ Note: The first character of the next line is escaped. So if it carries any special meaning (like & or |), that meaning will be lost and it will be interpreted as a pure text character (see last example at bottom).

Examples: (all tested on Windows XP and Windows 7)

xcopy file1.txt file2.txt 

can be written as:

xcopy^ file1.txt^ file2.txt 

or

xcopy ^ file1.txt ^ file2.txt 

or even

xc^ opy ^ file1.txt ^ file2.txt 

(That last works because there are no spaces betwen the xc and the ^, and no spaces at the beginning of the next line. So when you remove the ^ and the newline, you get...xcopy.)

For readability and sanity, it's probably best breaking only between parameters (be sure to include the space).

Be sure that the ^ is not the last thing in a batch file, as there appears to be a major issue with that.

Here's an example of character escaped at the start of the next line:

xcopy file1.txt file2.txt ^ & echo copied successfully 

This will not work because & will be escaped and lose its special meaning, thus sending all of "file1.txt file2.txt & echo copied successfully" as parameters to xcopy, causing an error (in this example).

To circumvent, add a space at the beginning of the next line.

(This is basically a rewrite of Wayne's answer but with the confusion around the caret cleared up. So I've posted it as a CW. I'm not shy about editing answers, but completely rewriting them seems inappropriate.)

Answer 4

Multiple commands can be put in parenthesis and spread over numerous lines; so something like echo hi && echo hello can be put like this:

( echo hi echo hello ) 

Also variables can help:

set AFILEPATH="C:\SOME\LONG\PATH\TO\A\FILE" if exist %AFILEPATH% ( start "" /b %AFILEPATH% -option C:\PATH\TO\SETTING... ) else ( ... 

Also I noticed with carets (^) that the if conditionals liked them to follow only if a space was present:

if exist ^ 

Answer 5

It seems however that splitting in the middle of the values of a for loop doesn't need a caret(and actually trying to use one will be considered a syntax error). For example,

for %n in (hello bye) do echo %n 

Note that no space is even needed after hello or before bye.

Answer 6

One thing I did not find when searching for 'how to split a long DOS batch file line' was how to split something containing long quoted text. In fact it IS covered in the answers above, but is not obvious. Use Caret to escape them. e.g.

myprog "needs this to be quoted" 

can be written as:

myprog ^"needs this ^ to be quoted^" 

but beware of starting a line with Caret after ending a line with caret - because it will come out as caret..?:

echo ^"^ needs this ^ to be quoted^ ^" 

-> "needs this to be quoted^"

Answer 7

Though the carret will be preferable way to do this here's one more approach using macro that constructs a command by the passed arguments:

@echo off :::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: set "{{=setlocal enableDelayedExpansion&for %%a in (" & set "}}="::end::" ) do if "%%~a" neq "::end::" (set command=!command! %%a) else (call !command! & endlocal)" ::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: %{{% echo "command" written on a few lines %}}% 

command is easier to read without the carets but using special symbols e.g. brackets,redirection and so on will break it. So you can use this for more simpler cases. Though you can still enclose parameters in double quotes