How can you find and replace text in a file using the Windows command-line environment?

***Note*** *- Be sure to see the update at the end of this answer for a link to the superior JREPL.BAT that supersedes REPL.BAT*
*[JREPL.BAT 7.0 and above](

[To see links please register here]

) natively supports unicode (UTF-16LE) via the `/UTF` option, as well as any other character set, including UTF-8, via ADO!!!!*

--------------------

[I have written a small hybrid JScript/batch utility called REPL.BAT](

[To see links please register here]

) that is very convenient for modifying ASCII (or extended ASCII) files via the command line or a batch file. The purely native script does not require installation of any 3rd party executeable, and it works on any modern Windows version from XP onward. It is also very fast, especially when compared to pure batch solutions.

REPL.BAT simply reads stdin, performs a JScript regex search and replace, and writes the result to stdout.

Here is a trivial example of how to replace foo with bar in test.txt, assuming REPL.BAT is in your current folder, or better yet, somewhere within your PATH:

type test.txt|repl "foo" "bar" >test.txt.new
move /y test.txt.new test.txt

The JScript regex capabilities make it very powerful, especially the ability of the replacement text to reference captured substrings from the search text.

I've included a number of options in the utility that make it quite powerful. For example, combining the `M` and `X` options enable modification of binary files! The `M` Multi-line option allows searches across multiple lines. The `X` eXtended substitution pattern option provides escape sequences that enable inclusion of any binary value in the replacement text.

The entire utility could have been written as pure JScript, but the hybrid batch file eliminates the need to explicitly specify CSCRIPT every time you want to use the utility.

Here is the REPL.BAT script. Full documentation is embedded within the script.

@if (@X)==(@Y) @end /* Harmless hybrid line that begins a JScript comment

::************ Documentation ***********
::REPL.BAT version 6.2
:::
:::REPL Search Replace [Options [SourceVar]]
:::REPL /?[REGEX|REPLACE]
:::REPL /V
:::
::: Performs a global regular expression search and replace operation on
::: each line of input from stdin and prints the result to stdout.
:::
::: Each parameter may be optionally enclosed by double quotes. The double
::: quotes are not considered part of the argument. The quotes are required
::: if the parameter contains a batch token delimiter like space, tab, comma,
::: semicolon. The quotes should also be used if the argument contains a
::: batch special character like &, |, etc. so that the special character
::: does not need to be escaped with ^.
:::
::: If called with a single argument of /?, then prints help documentation
::: to stdout. If a single argument of /?REGEX, then opens up Microsoft's
::: JScript regular expression documentation within your browser. If a single
::: argument of /?REPLACE, then opens up Microsoft's JScript REPLACE
::: documentation within your browser.
:::
::: If called with a single argument of /V, case insensitive, then prints
::: the version of REPL.BAT.
:::
::: Search - By default, this is a case sensitive JScript (ECMA) regular
::: expression expressed as a string.
:::
::: JScript regex syntax documentation is available at
:::

[To see links please register here]

:::
::: Replace - By default, this is the string to be used as a replacement for
::: each found search expression. Full support is provided for
::: substituion patterns available to the JScript replace method.
:::
::: For example, $& represents the portion of the source that matched
::: the entire search pattern, $1 represents the first captured
::: submatch, $2 the second captured submatch, etc. A $ literal
::: can be escaped as $$.
:::
::: An empty replacement string must be represented as "".
:::
::: Replace substitution pattern syntax is fully documented at
:::

[To see links please register here]

:::
::: Options - An optional string of characters used to alter the behavior
::: of REPL. The option characters are case insensitive, and may
::: appear in any order.
:::
::: A - Only print altered lines. Unaltered lines are discarded.
::: If the S options is present, then prints the result only if
::: there was a change anywhere in the string. The A option is
::: incompatible with the M option unless the S option is present.
:::
::: B - The Search must match the beginning of a line.
::: Mostly used with literal searches.
:::
::: E - The Search must match the end of a line.
::: Mostly used with literal searches.
:::
::: I - Makes the search case-insensitive.
:::
::: J - The Replace argument represents a JScript expression.
::: The expression may access an array like arguments object
::: named $. However, $ is not a true array object.
:::
::: The $.length property contains the total number of arguments
::: available. The $.length value is equal to n+3, where n is the
::: number of capturing left parentheses within the Search string.
:::
::: $[0] is the substring that matched the Search,
::: $[1] through $[n] are the captured submatch strings,
::: $[n+1] is the offset where the match occurred, and
::: $[n+2] is the original source string.
:::
::: Arguments $[0] through $[10] may be abbreviated as
::: $1 through $10. Argument $[11] and above must use the square
::: bracket notation.
:::
::: L - The Search is treated as a string literal instead of a
::: regular expression. Also, all $ found in the Replace string
::: are treated as $ literals.
:::
::: M - Multi-line mode. The entire contents of stdin is read and
::: processed in one pass instead of line by line, thus enabling
::: search for \n. This also enables preservation of the original
::: line terminators. If the M option is not present, then every
::: printed line is terminated with carriage return and line feed.
::: The M option is incompatible with the A option unless the S
::: option is also present.
:::
::: Note: If working with binary data containing NULL bytes,
::: then the M option must be used.
:::
::: S - The source is read from an environment variable instead of
::: from stdin. The name of the source environment variable is
::: specified in the next argument after the option string. Without
::: the M option, ^ anchors the beginning of the string, and $ the
::: end of the string. With the M option, ^ anchors the beginning
::: of a line, and $ the end of a line.
:::
::: V - Search and Replace represent the name of environment
::: variables that contain the respective values. An undefined
::: variable is treated as an empty string.
:::
::: X - Enables extended substitution pattern syntax with support
::: for the following escape sequences within the Replace string:
:::
::: \\ - Backslash
::: \b - Backspace
::: \f - Formfeed
::: \n - Newline
::: \q - Quote
::: \r - Carriage Return
::: \t - Horizontal Tab
::: \v - Vertical Tab
::: \xnn - Extended ASCII byte code expressed as 2 hex digits
::: \unnnn - Unicode character expressed as 4 hex digits
:::
::: Also enables the \q escape sequence for the Search string.
::: The other escape sequences are already standard for a regular
::: expression Search string.
:::
::: Also modifies the behavior of \xnn in the Search string to work
::: properly with extended ASCII byte codes.
:::
::: Extended escape sequences are supported even when the L option
::: is used. Both Search and Replace support all of the extended
::: escape sequences if both the X and L opions are combined.
:::
::: Return Codes: 0 = At least one change was made
::: or the /? or /V option was used
:::
::: 1 = No change was made
:::
::: 2 = Invalid call syntax or incompatible options
:::
::: 3 = JScript runtime error, typically due to invalid regex
:::
::: REPL.BAT was written by Dave Benham, with assistance from DosTips user Aacini
::: to get \xnn to work properly with extended ASCII byte codes. Also assistance
::: from DosTips user penpen diagnosing issues reading NULL bytes, along with a
::: workaround. REPL.BAT was originally posted at:
:::

[To see links please register here]

:::

::************ Batch portion ***********
@echo off
if .%2 equ . (
if "%~1" equ "/?" (
<"%~f0" cscript //E:JScript //nologo "%~f0" "^:::" "" a
exit /b 0
) else if /i "%~1" equ "/?regex" (
explorer "http://msdn.microsoft.com/en-us/library/ae5bf541(v=vs.80).aspx"
exit /b 0
) else if /i "%~1" equ "/?replace" (
explorer "http://msdn.microsoft.com/en-US/library/efy6s3e6(v=vs.80).aspx"
exit /b 0
) else if /i "%~1" equ "/V" (
<"%~f0" cscript //E:JScript //nologo "%~f0" "^::(REPL\.BAT version)" "$1" a
exit /b 0
) else (
call :err "Insufficient arguments"
exit /b 2
)
)
echo(%~3|findstr /i "[^SMILEBVXAJ]" >nul && (
call :err "Invalid option(s)"
exit /b 2
)
echo(%~3|findstr /i "M"|findstr /i "A"|findstr /vi "S" >nul && (
call :err "Incompatible options"
exit /b 2
)
cscript //E:JScript //nologo "%~f0" %*
exit /b %errorlevel%

:err
>&2 echo ERROR: %~1. Use REPL /? to get help.
exit /b

************* JScript portion **********/
var rtn=1;
try {
var env=WScript.CreateObject("WScript.Shell").Environment("Process");
var args=WScript.Arguments;
var search=args.Item(0);
var replace=args.Item(1);
var options="g";
if (args.length>2) options+=args.Item(2).toLowerCase();
var multi=(options.indexOf("m")>=0);
var alterations=(options.indexOf("a")>=0);
if (alterations) options=options.replace(/a/g,"");
var srcVar=(options.indexOf("s")>=0);
if (srcVar) options=options.replace(/s/g,"");
var jexpr=(options.indexOf("j")>=0);
if (jexpr) options=options.replace(/j/g,"");
if (options.indexOf("v")>=0) {
options=options.replace(/v/g,"");
search=env(search);
replace=env(replace);
}
if (options.indexOf("x")>=0) {
options=options.replace(/x/g,"");
if (!jexpr) {
replace=replace.replace(/\\\\/g,"\\B");
replace=replace.replace(/\\q/g,"\"");
replace=replace.replace(/\\x80/g,"\\u20AC");
replace=replace.replace(/\\x82/g,"\\u201A");
replace=replace.replace(/\\x83/g,"\\u0192");
replace=replace.replace(/\\x84/g,"\\u201E");
replace=replace.replace(/\\x85/g,"\\u2026");
replace=replace.replace(/\\x86/g,"\\u2020");
replace=replace.replace(/\\x87/g,"\\u2021");
replace=replace.replace(/\\x88/g,"\\u02C6");
replace=replace.replace(/\\x89/g,"\\u2030");
replace=replace.replace(/\\x8[aA]/g,"\\u0160");
replace=replace.replace(/\\x8[bB]/g,"\\u2039");
replace=replace.replace(/\\x8[cC]/g,"\\u0152");
replace=replace.replace(/\\x8[eE]/g,"\\u017D");
replace=replace.replace(/\\x91/g,"\\u2018");
replace=replace.replace(/\\x92/g,"\\u2019");
replace=replace.replace(/\\x93/g,"\\u201C");
replace=replace.replace(/\\x94/g,"\\u201D");
replace=replace.replace(/\\x95/g,"\\u2022");
replace=replace.replace(/\\x96/g,"\\u2013");
replace=replace.replace(/\\x97/g,"\\u2014");
replace=replace.replace(/\\x98/g,"\\u02DC");
replace=replace.replace(/\\x99/g,"\\u2122");
replace=replace.replace(/\\x9[aA]/g,"\\u0161");
replace=replace.replace(/\\x9[bB]/g,"\\u203A");
replace=replace.replace(/\\x9[cC]/g,"\\u0153");
replace=replace.replace(/\\x9[dD]/g,"\\u009D");
replace=replace.replace(/\\x9[eE]/g,"\\u017E");
replace=replace.replace(/\\x9[fF]/g,"\\u0178");
replace=replace.replace(/\\b/g,"\b");
replace=replace.replace(/\\f/g,"\f");
replace=replace.replace(/\\n/g,"\n");
replace=replace.replace(/\\r/g,"\r");
replace=replace.replace(/\\t/g,"\t");
replace=replace.replace(/\\v/g,"\v");
replace=replace.replace(/\\x[0-9a-fA-F]{2}|\\u[0-9a-fA-F]{4}/g,
function($0,$1,$2){
return String.fromCharCode(parseInt("0x"+$0.substring(2)));
}
);
replace=replace.replace(/\\B/g,"\\");
}
search=search.replace(/\\\\/g,"\\B");
search=search.replace(/\\q/g,"\"");
search=search.replace(/\\x80/g,"\\u20AC");
search=search.replace(/\\x82/g,"\\u201A");
search=search.replace(/\\x83/g,"\\u0192");
search=search.replace(/\\x84/g,"\\u201E");
search=search.replace(/\\x85/g,"\\u2026");
search=search.replace(/\\x86/g,"\\u2020");
search=search.replace(/\\x87/g,"\\u2021");
search=search.replace(/\\x88/g,"\\u02C6");
search=search.replace(/\\x89/g,"\\u2030");
search=search.replace(/\\x8[aA]/g,"\\u0160");
search=search.replace(/\\x8[bB]/g,"\\u2039");
search=search.replace(/\\x8[cC]/g,"\\u0152");
search=search.replace(/\\x8[eE]/g,"\\u017D");
search=search.replace(/\\x91/g,"\\u2018");
search=search.replace(/\\x92/g,"\\u2019");
search=search.replace(/\\x93/g,"\\u201C");
search=search.replace(/\\x94/g,"\\u201D");
search=search.replace(/\\x95/g,"\\u2022");
search=search.replace(/\\x96/g,"\\u2013");
search=search.replace(/\\x97/g,"\\u2014");
search=search.replace(/\\x98/g,"\\u02DC");
search=search.replace(/\\x99/g,"\\u2122");
search=search.replace(/\\x9[aA]/g,"\\u0161");
search=search.replace(/\\x9[bB]/g,"\\u203A");
search=search.replace(/\\x9[cC]/g,"\\u0153");
search=search.replace(/\\x9[dD]/g,"\\u009D");
search=search.replace(/\\x9[eE]/g,"\\u017E");
search=search.replace(/\\x9[fF]/g,"\\u0178");
if (options.indexOf("l")>=0) {
search=search.replace(/\\b/g,"\b");
search=search.replace(/\\f/g,"\f");
search=search.replace(/\\n/g,"\n");
search=search.replace(/\\r/g,"\r");
search=search.replace(/\\t/g,"\t");
search=search.replace(/\\v/g,"\v");
search=search.replace(/\\x[0-9a-fA-F]{2}|\\u[0-9a-fA-F]{4}/g,
function($0,$1,$2){
return String.fromCharCode(parseInt("0x"+$0.substring(2)));
}
);
search=search.replace(/\\B/g,"\\");
} else search=search.replace(/\\B/g,"\\\\");
}
if (options.indexOf("l")>=0) {
options=options.replace(/l/g,"");
search=search.replace(/([.^$*+?()[{\\|])/g,"\\$1");
if (!jexpr) replace=replace.replace(/\$/g,"$$$$");
}
if (options.indexOf("b")>=0) {
options=options.replace(/b/g,"");
search="^"+search
}
if (options.indexOf("e")>=0) {
options=options.replace(/e/g,"");
search=search+"$"
}
var search=new RegExp(search,options);
var str1, str2;

if (srcVar) {
str1=env(args.Item(3));
str2=str1.replace(search,jexpr?replFunc:replace);
if (!alterations || str1!=str2) if (multi) {
WScript.Stdout.Write(str2);
} else {
WScript.Stdout.WriteLine(str2);
}
if (str1!=str2) rtn=0;
} else if (multi){
var buf=1024;
str1="";
while (!WScript.StdIn.AtEndOfStream) {
str1+=WScript.StdIn.Read(buf);
buf*=2
}
str2=str1.replace(search,jexpr?replFunc:replace);
WScript.Stdout.Write(str2);
if (str1!=str2) rtn=0;
} else {
while (!WScript.StdIn.AtEndOfStream) {
str1=WScript.StdIn.ReadLine();
str2=str1.replace(search,jexpr?replFunc:replace);
if (!alterations || str1!=str2) WScript.Stdout.WriteLine(str2);
if (str1!=str2) rtn=0;
}
}
} catch(e) {
WScript.Stderr.WriteLine("JScript runtime error: "+e.message);
rtn=3;
}
WScript.Quit(rtn);

function replFunc($0, $1, $2, $3, $4, $5, $6, $7, $8, $9, $10) {
var $=arguments;
return(eval(replace));
}

<br/>
***IMPORTANT UPDATE***

I have ceased development of REPL.BAT, and replaced it with JREPL.BAT. This newer utility has all the same functionality of REPL.BAT, plus much more:

- Unicode UTF-16LE support via native CSCRIPT unicode capabilities, and any other character set (including UTF-8) via ADO.
- Read directly from / write directly to a file: no need for pipes, redirection, or move command.
- Incorporate user supplied JScript
- Translation facility similar to unix tr, only it also supports regex search and JScript replace
- Discard non-matching text
- Prefix output lines with line number
- and more...

As always, full documentation is embedded within the script.

The original trivial solution is now even simpler:

jrepl "foo" "bar" /f test.txt /o -

[The current version of JREPL.BAT is available at DosTips](

[To see links please register here]

). Read all of the subsequent posts in the thread to see examples of usage and a history of the development.