Windows CMD FOR loop - windows

I'm trying to make a code which will get first words from all lines of HELP's output to a variable and echo this variable. Here is my code:
#echo off
set a=
for /F "tokens=1,*" %%i in ('help') do (
set a=%a% %%i
)
echo %a%
But it returns first word from only last line. Why?

Bali C solved your problem as stated, but it looks to me like you are trying to get a list of commands found in HELP.
Some of the commands appear on multiple lines, so you get some extraneous words. Also there is a leading and trailing line beginning with "For" on an English machine that is not wanted.
Here is a short script for an English machine that will build a list of commands. The FINDSTR command will have to change for different languages.
#echo off
setlocal enableDelayedExpansion
set "cmds="
for /f "eol= delims=." %%A in ('help^|findstr /bv "For"') do (
for /f %%B in ("%%A") do set "cmds=!cmds! %%B"
)
set "cmds=%cmds:~1%"
echo %cmds%
EDIT
Ansgar Wiechers came up with a more efficient algorithm to extract just the command names at https://stackoverflow.com/a/12733642/1012053 that I believe should work with all languages. I've used his idea to simplify the code below.
#echo off
setlocal enableDelayedExpansion
set "cmds="
for /f %%A in ('help^|findstr /brc:"[A-Z][A-Z]* "') do set "cmds=!cmds! %%A"
set "cmds=%cmds:~1%"
echo %cmds%

You need to use delayed expansion in your for loop
#echo off
setlocal enabledelayedexpansion
set a=
for /F "tokens=1,*" %%i in ('help') do (
set a=!a! %%i
)
echo %a%
Instead of using %'s around the a variable, you use !'s to use delayed expansion.

Because the echo is outside the do ( ...... )
#echo off
for /F "tokens=1,*" %%i in ('help') do (
echo %%i
)
and no need to print a, you can use directly %%i.
Another very simple example could be a batch like this saved as help1.cmd
#echo off
for /F "tokens=1,*" %%i in ('help') do (
if /I "%%i" EQU "%1" echo %%j
)
and you call this batch like
help1 MKDIR
to get the short help text for the MKDIR command

Related

How to Store Dir and findStr result in variable in batch file [duplicate]

This question already has answers here:
Assign output of a program to a variable using a MS batch file
(12 answers)
Closed 9 months ago.
Is it possible to set a statement's output of a batch file to a variable, for example:
findstr testing > %VARIABLE%
echo %VARIABLE%
FOR /F "tokens=* USEBACKQ" %%F IN (`command`) DO (
SET var=%%F
)
ECHO %var%
I always use the USEBACKQ so that if you have a string to insert or a long file name, you can use your double quotes without screwing up the command.
Now if your output will contain multiple lines, you can do this
SETLOCAL ENABLEDELAYEDEXPANSION
SET count=1
FOR /F "tokens=* USEBACKQ" %%F IN (`command`) DO (
SET var!count!=%%F
SET /a count=!count!+1
)
ECHO %var1%
ECHO %var2%
ECHO %var3%
ENDLOCAL
In a single line:
FOR /F "tokens=*" %%g IN ('your command') do (SET VAR=%%g)
The command output will be set in %g then in VAR.
More information here: https://ss64.com/nt/for_cmd.html
I found this thread on that there Interweb thing. Boils down to:
#echo off
setlocal enableextensions
for /f "tokens=*" %%a in (
'VER'
) do (
set myvar=%%a
)
echo/%%myvar%%=%myvar%
pause
endlocal
You can also redirect the output of a command to a temporary file, and then put the contents of that temporary file into your variable, likesuchashereby. It doesn't work with multiline input though.
cmd > tmpFile
set /p myvar= < tmpFile
del tmpFile
Credit to the thread on Tom's Hardware.
If you don't want to output to a temp file and then read into a variable, this code stores result of command direct into a variable:
FOR /F %i IN ('findstr testing') DO set VARIABLE=%i
echo %VARIABLE%
If you want to enclose search string in double quotes:
FOR /F %i IN ('findstr "testing"') DO set VARIABLE=%i
If you want to store this code in a batch file, add an extra % symbol:
FOR /F %%i IN ('findstr "testing"') DO set VARIABLE=%%i
A useful example to count the number of files in a directory & store in a variable:
(illustrates piping)
FOR /F %i IN ('dir /b /a-d "%cd%" ^| find /v /c "?"') DO set /a count=%i
Note the use of single quotes instead of double quotes " or grave accent ` in the command brackets. This is cleaner alternative to delims, tokens or usebackq in for loop.
Update 27/8/2021:
Another method is to set errorlevel variable, although many would discourage setting errorlevel on large scripts or when new to cmd flavor of the installed OS variant.
This method works where (return) value to be stored is a 32-bit integer.
eg.
to count the number of files in a directory & store in a variable called errorlevel:
(dir /b /a-d ^| find /v /c "?") | (set /p myVar=& cmd /c exit /b %myVar%)
echo %errorlevel%
81
set /a %errorlevel%+1
82
REM Note: Win CMD arithmetic limit: 2147483647 (32-bit integers)
REM ie. an overflow would continue count at -2147483648
REM and reset again after reaching 2147483647
REM See tests below:
cmd /c exit /b 2147483647
echo %errorlevel%
2147483647
cmd /c exit /b 2147483648
echo %errorlevel%
-2147483648
cmd /c exit /b 2147483649
echo %errorlevel%
-2147483647
Above method can be modified to return encoded strings to be decoded in parent process (within 32 bit limitation).
A 3rd illustration, although of limited use (because the variable is set in child process, not parent) is:
(dir /b /a-d ^| find /v /c "?") | (set /p myVar=& set myVar)
In this case the value of myVar is set to the number of files in the directory
Tested on Win 10 CMD.
To read a file...
set /P Variable=<File.txt
To Write a file
#echo %DataToWrite%>File.txt
note; having spaces before the <> character causes a space to be added at the end of the variable, also
To add to a file,like a logger program,
First make a file with a single enter key in it called e.txt
set /P Data=<log0.log
set /P Ekey=<e.txt
#echo %Data%%Ekey%%NewData%>log0.txt
your log will look like this
Entry1
Entry2
and so on
Anyways a couple useful things
These answers were all so close to the answer that I needed. This is an attempt to expand on them.
In a Batch file
If you're running from within a .bat file and you want a single line that allows you to export a complicated command like jq -r ".Credentials.AccessKeyId" c:\temp\mfa-getCreds.json to a variable named AWS_ACCESS_KEY then you want this:
FOR /F "tokens=* USEBACKQ" %%g IN (`jq -r ".Credentials.AccessKeyId" c:\temp\mfa-getCreds.json`) do (SET "AWS_ACCESS_KEY=%%g")
On the Command Line
If you're at the C:\ prompt you want a single line that allows you to run a complicated command like jq -r ".Credentials.AccessKeyId" c:\temp\mfa-getCreds.json to a variable named AWS_ACCESS_KEY then you want this:
FOR /F "tokens=* USEBACKQ" %g IN (`jq -r ".Credentials.AccessKeyId" c:\temp\mfa-getCreds.json`) do (SET "AWS_ACCESS_KEY=%g")
Explanation
The only difference between the two answers above is that on the command line, you use a single % in your variable. In a batch file, you have to double up on the percentage signs (%%).
Since the command includes colons, quotes, and parentheses, you need to include the USEBACKQ line in the options so that you can use backquotes to specify the command to run and then all kinds of funny characters inside of it.
Some notes and some tricks.
The 'official' way to assign result to a variable is with FOR /F though in the other answers is shown how a temporary file can be used also.
For command processing FOR command has two forms depending if the usebackq option is used. In the all examples below the whole output is used without splitting it.
FOR /f "tokens=* delims=" %%A in ('whoami') do #set "I-Am=%%A"
FOR /f "usebackq tokens=* delims=" %%A in (`whoami`) do #set "I-Am=%%A"
and if used directly in the console:
FOR /f "tokens=* delims=" %A in ('whoami') do set "I-Am=%A"
FOR /f "usebackq tokens=* delims=" %A in (`whoami`) do set "I-Am=%A"
%%A is a temporary variable available only on the FOR command context and is called token.The two forms can be useful in case when you are dealing with arguments containing specific quotes. It is especially useful with REPL interfaces of other languages or WMIC.
Though in both cases the expression can be put in double quotes and it still be processed.
Here's an example with python (it is possible to transition the expression in the brackets on a separate line which is used for easier reading):
#echo off
for /f "tokens=* delims=" %%a in (
'"python -c ""print("""Message from python""")"""'
) do (
echo processed message from python: "%%a"
)
To use an assigned variable in the same FOR block check also the DELAYED EXPANSION
And some tricks
To save yourself from writing all the arguments for the FOR command you can use MACRO for assigning the result to variable:
#echo off
::::: ---- defining the assign macro ---- ::::::::
setlocal DisableDelayedExpansion
(set LF=^
%=EMPTY=%
)
set ^"\n=^^^%LF%%LF%^%LF%%LF%^^"
::set argv=Empty
set assign=for /L %%n in (1 1 2) do ( %\n%
if %%n==2 (%\n%
setlocal enableDelayedExpansion%\n%
for /F "tokens=1,2 delims=," %%A in ("!argv!") do (%\n%
for /f "tokens=* delims=" %%# in ('%%~A') do endlocal^&set "%%~B=%%#" %\n%
) %\n%
) %\n%
) ^& set argv=,
::::: -------- ::::::::
:::EXAMPLE
%assign% "WHOAMI /LOGONID",result
echo %result%
the first argument to the macro is the command and the second the name of the variable we want to use and both are separated by , (comma). Though this is suitable only for straight forward scenarios.
If we want a similar macro for the console we can use DOSKEY
doskey assign=for /f "tokens=1,2 delims=," %a in ("$*") do #for /f "tokens=* delims=" %# in ('"%a"') do #set "%b=%#"
rem -- example --
assign WHOAMI /LOGONID,my-id
echo %my-id%
DOSKEY does accept double quotes as enclosion for arguments so this also is useful for more simple scenarios.
FOR also works well with pipes which can be used for chaining commands (though it is not so good for assigning a variable.
hostname |for /f "tokens=* delims=" %%# in ('more') do #(ping %%#)
Which also can be beautified with macros:
#echo off
:: --- defining chain command macros ---
set "result-as-[arg]:=|for /f "tokens=* delims=" %%# in ('more') do #("
set "[arg]= %%#)"
::: -------------------------- :::
::Example:
hostname %result-as-[arg]:% ping %[arg]%
And for completnes macros for the temp file approach (no doskey definition ,but it also can be easy done.If you have a SSD this wont be so slow):
#echo off
:::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
set "[[=>"#" 2>&1&set/p "&set "]]==<# & del /q # >nul 2>&1"
:::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
chcp %[[%code-page%]]%
echo ~~%code-page%~~
whoami %[[%its-me%]]%
echo ##%its-me%##
For /f with another macro:
::::::::::::::::::::::::::::::::::::::::::::::::::
;;set "{{=for /f "tokens=* delims=" %%# in ('" &::
;;set "--=') do #set "" &::
;;set "}}==%%#"" &::
::::::::::::::::::::::::::::::::::::::::::::::::::
:: --examples
::assigning ver output to %win-ver% variable
%{{% ver %--%win-ver%}}%
echo 3: %win-ver%
::assigning hostname output to %my-host% variable
%{{% hostname %--%my-host%}}%
echo 4: %my-host%
cd %windir%\system32\inetsrv
#echo off
for /F "tokens=* USEBACKQ" %%x in (
`appcmd list apppool /text:name`
) do (
echo|set /p= "%%x - " /text:name & appcmd.exe list apppool "%%x" /text:processModel.identityType
)
echo %date% & echo %time%
pause
I most cases, creating a temporary file named after your variable name might be acceptable. (as you are probably using meaningful variables name...)
Here, my variable name is SSH_PAGEANT_AUTH_SOCK
dir /w "\\.\pipe\\"|find "pageant" > %temp%\SSH_PAGEANT_AUTH_SOCK && set /P SSH_PAGEANT_AUTH_SOCK=<%temp%\SSH_PAGEANT_AUTH_SOCK

How to store python version in a variable inside .bat file in an easy way? [duplicate]

This question already has answers here:
Assign output of a program to a variable using a MS batch file
(12 answers)
Closed 9 months ago.
Is it possible to set a statement's output of a batch file to a variable, for example:
findstr testing > %VARIABLE%
echo %VARIABLE%
FOR /F "tokens=* USEBACKQ" %%F IN (`command`) DO (
SET var=%%F
)
ECHO %var%
I always use the USEBACKQ so that if you have a string to insert or a long file name, you can use your double quotes without screwing up the command.
Now if your output will contain multiple lines, you can do this
SETLOCAL ENABLEDELAYEDEXPANSION
SET count=1
FOR /F "tokens=* USEBACKQ" %%F IN (`command`) DO (
SET var!count!=%%F
SET /a count=!count!+1
)
ECHO %var1%
ECHO %var2%
ECHO %var3%
ENDLOCAL
In a single line:
FOR /F "tokens=*" %%g IN ('your command') do (SET VAR=%%g)
The command output will be set in %g then in VAR.
More information here: https://ss64.com/nt/for_cmd.html
I found this thread on that there Interweb thing. Boils down to:
#echo off
setlocal enableextensions
for /f "tokens=*" %%a in (
'VER'
) do (
set myvar=%%a
)
echo/%%myvar%%=%myvar%
pause
endlocal
You can also redirect the output of a command to a temporary file, and then put the contents of that temporary file into your variable, likesuchashereby. It doesn't work with multiline input though.
cmd > tmpFile
set /p myvar= < tmpFile
del tmpFile
Credit to the thread on Tom's Hardware.
If you don't want to output to a temp file and then read into a variable, this code stores result of command direct into a variable:
FOR /F %i IN ('findstr testing') DO set VARIABLE=%i
echo %VARIABLE%
If you want to enclose search string in double quotes:
FOR /F %i IN ('findstr "testing"') DO set VARIABLE=%i
If you want to store this code in a batch file, add an extra % symbol:
FOR /F %%i IN ('findstr "testing"') DO set VARIABLE=%%i
A useful example to count the number of files in a directory & store in a variable:
(illustrates piping)
FOR /F %i IN ('dir /b /a-d "%cd%" ^| find /v /c "?"') DO set /a count=%i
Note the use of single quotes instead of double quotes " or grave accent ` in the command brackets. This is cleaner alternative to delims, tokens or usebackq in for loop.
Update 27/8/2021:
Another method is to set errorlevel variable, although many would discourage setting errorlevel on large scripts or when new to cmd flavor of the installed OS variant.
This method works where (return) value to be stored is a 32-bit integer.
eg.
to count the number of files in a directory & store in a variable called errorlevel:
(dir /b /a-d ^| find /v /c "?") | (set /p myVar=& cmd /c exit /b %myVar%)
echo %errorlevel%
81
set /a %errorlevel%+1
82
REM Note: Win CMD arithmetic limit: 2147483647 (32-bit integers)
REM ie. an overflow would continue count at -2147483648
REM and reset again after reaching 2147483647
REM See tests below:
cmd /c exit /b 2147483647
echo %errorlevel%
2147483647
cmd /c exit /b 2147483648
echo %errorlevel%
-2147483648
cmd /c exit /b 2147483649
echo %errorlevel%
-2147483647
Above method can be modified to return encoded strings to be decoded in parent process (within 32 bit limitation).
A 3rd illustration, although of limited use (because the variable is set in child process, not parent) is:
(dir /b /a-d ^| find /v /c "?") | (set /p myVar=& set myVar)
In this case the value of myVar is set to the number of files in the directory
Tested on Win 10 CMD.
To read a file...
set /P Variable=<File.txt
To Write a file
#echo %DataToWrite%>File.txt
note; having spaces before the <> character causes a space to be added at the end of the variable, also
To add to a file,like a logger program,
First make a file with a single enter key in it called e.txt
set /P Data=<log0.log
set /P Ekey=<e.txt
#echo %Data%%Ekey%%NewData%>log0.txt
your log will look like this
Entry1
Entry2
and so on
Anyways a couple useful things
These answers were all so close to the answer that I needed. This is an attempt to expand on them.
In a Batch file
If you're running from within a .bat file and you want a single line that allows you to export a complicated command like jq -r ".Credentials.AccessKeyId" c:\temp\mfa-getCreds.json to a variable named AWS_ACCESS_KEY then you want this:
FOR /F "tokens=* USEBACKQ" %%g IN (`jq -r ".Credentials.AccessKeyId" c:\temp\mfa-getCreds.json`) do (SET "AWS_ACCESS_KEY=%%g")
On the Command Line
If you're at the C:\ prompt you want a single line that allows you to run a complicated command like jq -r ".Credentials.AccessKeyId" c:\temp\mfa-getCreds.json to a variable named AWS_ACCESS_KEY then you want this:
FOR /F "tokens=* USEBACKQ" %g IN (`jq -r ".Credentials.AccessKeyId" c:\temp\mfa-getCreds.json`) do (SET "AWS_ACCESS_KEY=%g")
Explanation
The only difference between the two answers above is that on the command line, you use a single % in your variable. In a batch file, you have to double up on the percentage signs (%%).
Since the command includes colons, quotes, and parentheses, you need to include the USEBACKQ line in the options so that you can use backquotes to specify the command to run and then all kinds of funny characters inside of it.
Some notes and some tricks.
The 'official' way to assign result to a variable is with FOR /F though in the other answers is shown how a temporary file can be used also.
For command processing FOR command has two forms depending if the usebackq option is used. In the all examples below the whole output is used without splitting it.
FOR /f "tokens=* delims=" %%A in ('whoami') do #set "I-Am=%%A"
FOR /f "usebackq tokens=* delims=" %%A in (`whoami`) do #set "I-Am=%%A"
and if used directly in the console:
FOR /f "tokens=* delims=" %A in ('whoami') do set "I-Am=%A"
FOR /f "usebackq tokens=* delims=" %A in (`whoami`) do set "I-Am=%A"
%%A is a temporary variable available only on the FOR command context and is called token.The two forms can be useful in case when you are dealing with arguments containing specific quotes. It is especially useful with REPL interfaces of other languages or WMIC.
Though in both cases the expression can be put in double quotes and it still be processed.
Here's an example with python (it is possible to transition the expression in the brackets on a separate line which is used for easier reading):
#echo off
for /f "tokens=* delims=" %%a in (
'"python -c ""print("""Message from python""")"""'
) do (
echo processed message from python: "%%a"
)
To use an assigned variable in the same FOR block check also the DELAYED EXPANSION
And some tricks
To save yourself from writing all the arguments for the FOR command you can use MACRO for assigning the result to variable:
#echo off
::::: ---- defining the assign macro ---- ::::::::
setlocal DisableDelayedExpansion
(set LF=^
%=EMPTY=%
)
set ^"\n=^^^%LF%%LF%^%LF%%LF%^^"
::set argv=Empty
set assign=for /L %%n in (1 1 2) do ( %\n%
if %%n==2 (%\n%
setlocal enableDelayedExpansion%\n%
for /F "tokens=1,2 delims=," %%A in ("!argv!") do (%\n%
for /f "tokens=* delims=" %%# in ('%%~A') do endlocal^&set "%%~B=%%#" %\n%
) %\n%
) %\n%
) ^& set argv=,
::::: -------- ::::::::
:::EXAMPLE
%assign% "WHOAMI /LOGONID",result
echo %result%
the first argument to the macro is the command and the second the name of the variable we want to use and both are separated by , (comma). Though this is suitable only for straight forward scenarios.
If we want a similar macro for the console we can use DOSKEY
doskey assign=for /f "tokens=1,2 delims=," %a in ("$*") do #for /f "tokens=* delims=" %# in ('"%a"') do #set "%b=%#"
rem -- example --
assign WHOAMI /LOGONID,my-id
echo %my-id%
DOSKEY does accept double quotes as enclosion for arguments so this also is useful for more simple scenarios.
FOR also works well with pipes which can be used for chaining commands (though it is not so good for assigning a variable.
hostname |for /f "tokens=* delims=" %%# in ('more') do #(ping %%#)
Which also can be beautified with macros:
#echo off
:: --- defining chain command macros ---
set "result-as-[arg]:=|for /f "tokens=* delims=" %%# in ('more') do #("
set "[arg]= %%#)"
::: -------------------------- :::
::Example:
hostname %result-as-[arg]:% ping %[arg]%
And for completnes macros for the temp file approach (no doskey definition ,but it also can be easy done.If you have a SSD this wont be so slow):
#echo off
:::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
set "[[=>"#" 2>&1&set/p "&set "]]==<# & del /q # >nul 2>&1"
:::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
chcp %[[%code-page%]]%
echo ~~%code-page%~~
whoami %[[%its-me%]]%
echo ##%its-me%##
For /f with another macro:
::::::::::::::::::::::::::::::::::::::::::::::::::
;;set "{{=for /f "tokens=* delims=" %%# in ('" &::
;;set "--=') do #set "" &::
;;set "}}==%%#"" &::
::::::::::::::::::::::::::::::::::::::::::::::::::
:: --examples
::assigning ver output to %win-ver% variable
%{{% ver %--%win-ver%}}%
echo 3: %win-ver%
::assigning hostname output to %my-host% variable
%{{% hostname %--%my-host%}}%
echo 4: %my-host%
cd %windir%\system32\inetsrv
#echo off
for /F "tokens=* USEBACKQ" %%x in (
`appcmd list apppool /text:name`
) do (
echo|set /p= "%%x - " /text:name & appcmd.exe list apppool "%%x" /text:processModel.identityType
)
echo %date% & echo %time%
pause
I most cases, creating a temporary file named after your variable name might be acceptable. (as you are probably using meaningful variables name...)
Here, my variable name is SSH_PAGEANT_AUTH_SOCK
dir /w "\\.\pipe\\"|find "pageant" > %temp%\SSH_PAGEANT_AUTH_SOCK && set /P SSH_PAGEANT_AUTH_SOCK=<%temp%\SSH_PAGEANT_AUTH_SOCK

Echo first three characters of filenames in CMD Windows

for /r %g in (*.html) do echo %~ng:~0,3%
This does not work. I have tested a lot, but could not find the answer.
How do you echo the first three characters of all HTML-filenames?
#ECHO OFF
SETLOCAL
:: first way:
FOR /r %%g IN (*.html) DO (
SET "var=%%~ng"
CALL ECHO %%var:~0,3%%
)
pause
:: second way:
SETLOCAL ENABLEDELAYEDEXPANSION
FOR /r %%g IN (*.html) DO (
SET "var=%%~ng"
ECHO !var:~0,3!
)
GOTO :EOF
The fundamental issue is that substringing must be applied to an ordinary environment variable, not to a metavariable.

How to set commands output as a variable in a batch file [duplicate]

This question already has answers here:
Assign output of a program to a variable using a MS batch file
(12 answers)
Closed 9 months ago.
Is it possible to set a statement's output of a batch file to a variable, for example:
findstr testing > %VARIABLE%
echo %VARIABLE%
FOR /F "tokens=* USEBACKQ" %%F IN (`command`) DO (
SET var=%%F
)
ECHO %var%
I always use the USEBACKQ so that if you have a string to insert or a long file name, you can use your double quotes without screwing up the command.
Now if your output will contain multiple lines, you can do this
SETLOCAL ENABLEDELAYEDEXPANSION
SET count=1
FOR /F "tokens=* USEBACKQ" %%F IN (`command`) DO (
SET var!count!=%%F
SET /a count=!count!+1
)
ECHO %var1%
ECHO %var2%
ECHO %var3%
ENDLOCAL
In a single line:
FOR /F "tokens=*" %%g IN ('your command') do (SET VAR=%%g)
The command output will be set in %g then in VAR.
More information here: https://ss64.com/nt/for_cmd.html
I found this thread on that there Interweb thing. Boils down to:
#echo off
setlocal enableextensions
for /f "tokens=*" %%a in (
'VER'
) do (
set myvar=%%a
)
echo/%%myvar%%=%myvar%
pause
endlocal
You can also redirect the output of a command to a temporary file, and then put the contents of that temporary file into your variable, likesuchashereby. It doesn't work with multiline input though.
cmd > tmpFile
set /p myvar= < tmpFile
del tmpFile
Credit to the thread on Tom's Hardware.
If you don't want to output to a temp file and then read into a variable, this code stores result of command direct into a variable:
FOR /F %i IN ('findstr testing') DO set VARIABLE=%i
echo %VARIABLE%
If you want to enclose search string in double quotes:
FOR /F %i IN ('findstr "testing"') DO set VARIABLE=%i
If you want to store this code in a batch file, add an extra % symbol:
FOR /F %%i IN ('findstr "testing"') DO set VARIABLE=%%i
A useful example to count the number of files in a directory & store in a variable:
(illustrates piping)
FOR /F %i IN ('dir /b /a-d "%cd%" ^| find /v /c "?"') DO set /a count=%i
Note the use of single quotes instead of double quotes " or grave accent ` in the command brackets. This is cleaner alternative to delims, tokens or usebackq in for loop.
Update 27/8/2021:
Another method is to set errorlevel variable, although many would discourage setting errorlevel on large scripts or when new to cmd flavor of the installed OS variant.
This method works where (return) value to be stored is a 32-bit integer.
eg.
to count the number of files in a directory & store in a variable called errorlevel:
(dir /b /a-d ^| find /v /c "?") | (set /p myVar=& cmd /c exit /b %myVar%)
echo %errorlevel%
81
set /a %errorlevel%+1
82
REM Note: Win CMD arithmetic limit: 2147483647 (32-bit integers)
REM ie. an overflow would continue count at -2147483648
REM and reset again after reaching 2147483647
REM See tests below:
cmd /c exit /b 2147483647
echo %errorlevel%
2147483647
cmd /c exit /b 2147483648
echo %errorlevel%
-2147483648
cmd /c exit /b 2147483649
echo %errorlevel%
-2147483647
Above method can be modified to return encoded strings to be decoded in parent process (within 32 bit limitation).
A 3rd illustration, although of limited use (because the variable is set in child process, not parent) is:
(dir /b /a-d ^| find /v /c "?") | (set /p myVar=& set myVar)
In this case the value of myVar is set to the number of files in the directory
Tested on Win 10 CMD.
To read a file...
set /P Variable=<File.txt
To Write a file
#echo %DataToWrite%>File.txt
note; having spaces before the <> character causes a space to be added at the end of the variable, also
To add to a file,like a logger program,
First make a file with a single enter key in it called e.txt
set /P Data=<log0.log
set /P Ekey=<e.txt
#echo %Data%%Ekey%%NewData%>log0.txt
your log will look like this
Entry1
Entry2
and so on
Anyways a couple useful things
These answers were all so close to the answer that I needed. This is an attempt to expand on them.
In a Batch file
If you're running from within a .bat file and you want a single line that allows you to export a complicated command like jq -r ".Credentials.AccessKeyId" c:\temp\mfa-getCreds.json to a variable named AWS_ACCESS_KEY then you want this:
FOR /F "tokens=* USEBACKQ" %%g IN (`jq -r ".Credentials.AccessKeyId" c:\temp\mfa-getCreds.json`) do (SET "AWS_ACCESS_KEY=%%g")
On the Command Line
If you're at the C:\ prompt you want a single line that allows you to run a complicated command like jq -r ".Credentials.AccessKeyId" c:\temp\mfa-getCreds.json to a variable named AWS_ACCESS_KEY then you want this:
FOR /F "tokens=* USEBACKQ" %g IN (`jq -r ".Credentials.AccessKeyId" c:\temp\mfa-getCreds.json`) do (SET "AWS_ACCESS_KEY=%g")
Explanation
The only difference between the two answers above is that on the command line, you use a single % in your variable. In a batch file, you have to double up on the percentage signs (%%).
Since the command includes colons, quotes, and parentheses, you need to include the USEBACKQ line in the options so that you can use backquotes to specify the command to run and then all kinds of funny characters inside of it.
Some notes and some tricks.
The 'official' way to assign result to a variable is with FOR /F though in the other answers is shown how a temporary file can be used also.
For command processing FOR command has two forms depending if the usebackq option is used. In the all examples below the whole output is used without splitting it.
FOR /f "tokens=* delims=" %%A in ('whoami') do #set "I-Am=%%A"
FOR /f "usebackq tokens=* delims=" %%A in (`whoami`) do #set "I-Am=%%A"
and if used directly in the console:
FOR /f "tokens=* delims=" %A in ('whoami') do set "I-Am=%A"
FOR /f "usebackq tokens=* delims=" %A in (`whoami`) do set "I-Am=%A"
%%A is a temporary variable available only on the FOR command context and is called token.The two forms can be useful in case when you are dealing with arguments containing specific quotes. It is especially useful with REPL interfaces of other languages or WMIC.
Though in both cases the expression can be put in double quotes and it still be processed.
Here's an example with python (it is possible to transition the expression in the brackets on a separate line which is used for easier reading):
#echo off
for /f "tokens=* delims=" %%a in (
'"python -c ""print("""Message from python""")"""'
) do (
echo processed message from python: "%%a"
)
To use an assigned variable in the same FOR block check also the DELAYED EXPANSION
And some tricks
To save yourself from writing all the arguments for the FOR command you can use MACRO for assigning the result to variable:
#echo off
::::: ---- defining the assign macro ---- ::::::::
setlocal DisableDelayedExpansion
(set LF=^
%=EMPTY=%
)
set ^"\n=^^^%LF%%LF%^%LF%%LF%^^"
::set argv=Empty
set assign=for /L %%n in (1 1 2) do ( %\n%
if %%n==2 (%\n%
setlocal enableDelayedExpansion%\n%
for /F "tokens=1,2 delims=," %%A in ("!argv!") do (%\n%
for /f "tokens=* delims=" %%# in ('%%~A') do endlocal^&set "%%~B=%%#" %\n%
) %\n%
) %\n%
) ^& set argv=,
::::: -------- ::::::::
:::EXAMPLE
%assign% "WHOAMI /LOGONID",result
echo %result%
the first argument to the macro is the command and the second the name of the variable we want to use and both are separated by , (comma). Though this is suitable only for straight forward scenarios.
If we want a similar macro for the console we can use DOSKEY
doskey assign=for /f "tokens=1,2 delims=," %a in ("$*") do #for /f "tokens=* delims=" %# in ('"%a"') do #set "%b=%#"
rem -- example --
assign WHOAMI /LOGONID,my-id
echo %my-id%
DOSKEY does accept double quotes as enclosion for arguments so this also is useful for more simple scenarios.
FOR also works well with pipes which can be used for chaining commands (though it is not so good for assigning a variable.
hostname |for /f "tokens=* delims=" %%# in ('more') do #(ping %%#)
Which also can be beautified with macros:
#echo off
:: --- defining chain command macros ---
set "result-as-[arg]:=|for /f "tokens=* delims=" %%# in ('more') do #("
set "[arg]= %%#)"
::: -------------------------- :::
::Example:
hostname %result-as-[arg]:% ping %[arg]%
And for completnes macros for the temp file approach (no doskey definition ,but it also can be easy done.If you have a SSD this wont be so slow):
#echo off
:::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
set "[[=>"#" 2>&1&set/p "&set "]]==<# & del /q # >nul 2>&1"
:::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
chcp %[[%code-page%]]%
echo ~~%code-page%~~
whoami %[[%its-me%]]%
echo ##%its-me%##
For /f with another macro:
::::::::::::::::::::::::::::::::::::::::::::::::::
;;set "{{=for /f "tokens=* delims=" %%# in ('" &::
;;set "--=') do #set "" &::
;;set "}}==%%#"" &::
::::::::::::::::::::::::::::::::::::::::::::::::::
:: --examples
::assigning ver output to %win-ver% variable
%{{% ver %--%win-ver%}}%
echo 3: %win-ver%
::assigning hostname output to %my-host% variable
%{{% hostname %--%my-host%}}%
echo 4: %my-host%
cd %windir%\system32\inetsrv
#echo off
for /F "tokens=* USEBACKQ" %%x in (
`appcmd list apppool /text:name`
) do (
echo|set /p= "%%x - " /text:name & appcmd.exe list apppool "%%x" /text:processModel.identityType
)
echo %date% & echo %time%
pause
I most cases, creating a temporary file named after your variable name might be acceptable. (as you are probably using meaningful variables name...)
Here, my variable name is SSH_PAGEANT_AUTH_SOCK
dir /w "\\.\pipe\\"|find "pageant" > %temp%\SSH_PAGEANT_AUTH_SOCK && set /P SSH_PAGEANT_AUTH_SOCK=<%temp%\SSH_PAGEANT_AUTH_SOCK

How do I get the result of a command in a variable in windows? [duplicate]

This question already has answers here:
Assign output of a program to a variable using a MS batch file
(12 answers)
How to set commands output as a variable in a batch file [duplicate]
(9 answers)
Closed 9 months ago.
I'm looking to get the result of a command as a variable in a Windows batch script (see how to get the result of a command in bash for the bash scripting equivalent). A solution that will work in a .bat file is preferred, but other common windows scripting solutions are also welcome.
The humble for command has accumulated some interesting capabilities over the years:
D:\> FOR /F "delims=" %i IN ('date /t') DO set today=%i
D:\> echo %today%
Sat 20/09/2008
Note that "delims=" overwrites the default space and tab delimiters so that the output of the date command gets gobbled all at once.
To capture multi-line output, it can still essentially be a one-liner (using the variable lf as the delimiter in the resulting variable):
REM NB:in a batch file, need to use %%i not %i
setlocal EnableDelayedExpansion
SET lf=-
FOR /F "delims=" %%i IN ('dir \ /b') DO if ("!out!"=="") (set out=%%i) else (set out=!out!%lf%%%i)
ECHO %out%
To capture a piped expression, use ^|:
FOR /F "delims=" %%i IN ('svn info . ^| findstr "Root:"') DO set "URL=%%i"
If you have to capture all the command output you can use a batch like this:
#ECHO OFF
IF NOT "%1"=="" GOTO ADDV
SET VAR=
FOR /F %%I IN ('DIR *.TXT /B /O:D') DO CALL %0 %%I
SET VAR
GOTO END
:ADDV
SET VAR=%VAR%!%1
:END
All output lines are stored in VAR separated with "!".
But if only a single-line console-output is expected, try:
#ECHO off
#SET MY_VAR=
FOR /F %%I IN ('npm prefix') DO #SET "MY_VAR=%%I"
#REM Do something with MY_VAR variable...
#John: is there any practical use for this? I think you should watch PowerShell or any other programming language capable to perform scripting tasks easily (Python, Perl, PHP, Ruby)
To get the current directory, you can use this:
CD > tmpFile
SET /p myvar= < tmpFile
DEL tmpFile
echo test: %myvar%
It's using a temp-file though, so it's not the most pretty, but it certainly works! 'CD' puts the current directory in 'tmpFile', 'SET' loads the content of tmpFile.
Here is a solution for multiple lines with "array's":
#echo off
rem ---------
rem Obtain line numbers from the file
rem ---------
rem This is the file that is being read: You can replace this with %1 for dynamic behaviour or replace it with some command like the first example i gave with the 'CD' command.
set _readfile=test.txt
for /f "usebackq tokens=2 delims=:" %%a in (`find /c /v "" %_readfile%`) do set _max=%%a
set /a _max+=1
set _i=0
set _filename=temp.dat
rem ---------
rem Make the list
rem ---------
:makeList
find /n /v "" %_readfile% >%_filename%
rem ---------
rem Read the list
rem ---------
:readList
if %_i%==%_max% goto printList
rem ---------
rem Read the lines into the array
rem ---------
for /f "usebackq delims=] tokens=2" %%a in (`findstr /r "\[%_i%]" %_filename%`) do set _data%_i%=%%a
set /a _i+=1
goto readList
:printList
del %_filename%
set _i=1
:printMore
if %_i%==%_max% goto finished
set _data%_i%
set /a _i+=1
goto printMore
:finished
But you might want to consider moving to another more powerful shell or create an application for this stuff. It's stretching the possibilities of the batch files quite a bit.
you need to use the SET command with parameter /P and direct your output to it.
For example see http://www.ss64.com/nt/set.html. Will work for CMD, not sure about .BAT files
From a comment to this post:
That link has the command "Set /P
_MyVar=<MyFilename.txt" which says it will set _MyVar to the first line
from MyFilename.txt. This could be
used as "myCmd > tmp.txt" with "set
/P myVar=<tmp.txt". But it will only
get the first line of the output, not
all the output
Example to set in the "V" environment variable the most recent file
FOR /F %I IN ('DIR *.* /O:D /B') DO SET V=%I
in a batch file you have to use double prefix in the loop variable:
FOR /F %%I IN ('DIR *.* /O:D /B') DO SET V=%%I
I would like to add a remark to the above solutions:
All these syntaxes work perfectly well IF YOUR COMMAND IS FOUND WITHIN THE PATH or IF THE COMMAND IS A cmdpath WITHOUT SPACES OR SPECIAL CHARACTERS.
But if you try to use an executable command located in a folder which path contains special characters then you would need to enclose your command path into double quotes (") and then the FOR /F syntax does not work.
Examples:
$ for /f "tokens=* USEBACKQ" %f in (
`""F:\GLW7\Distrib\System\Shells and scripting\f2ko.de\folderbrowse.exe"" Hello '"F:\GLW7\Distrib\System\Shells and scripting"'`
) do echo %f
The filename, directory name, or volume label syntax is incorrect.
or
$ for /f "tokens=* USEBACKQ" %f in (
`"F:\GLW7\Distrib\System\Shells and scripting\f2ko.de\folderbrowse.exe" "Hello World" "F:\GLW7\Distrib\System\Shells and scripting"`
) do echo %f
'F:\GLW7\Distrib\System\Shells' is not recognized as an internal or external command, operable program or batch file.
or
`$ for /f "tokens=* USEBACKQ" %f in (
`""F:\GLW7\Distrib\System\Shells and scripting\f2ko.de\folderbrowse.exe"" "Hello World" "F:\GLW7\Distrib\System\Shells and scripting"`
) do echo %f
'"F:\GLW7\Distrib\System\Shells and scripting\f2ko.de\folderbrowse.exe"" "Hello' is not recognized as an internal or external command, operable program or batch file.
In that case, the only solution I found to use a command and store its result in a variable is to set (temporarily) the default directory to the one of command itself :
pushd "%~d0%~p0"
FOR /F "tokens=* USEBACKQ" %%F IN (
`FOLDERBROWSE "Hello world!" "F:\GLW7\Distrib\System\Layouts (print,display...)"`
) DO (SET MyFolder=%%F)
popd
echo My selected folder: %MyFolder%
The result is then correct:
My selected folder: F:\GLW7\Distrib\System\OS install, recovery, VM\
Press any key to continue . . .
Of course in the above example, I assume that my batch script is located in the same folder as the one of my executable command so that I can use the "%~d0%~p0" syntax. If this is not your case, then you have to find a way to locate your command path and change the default directory to its path.
NB: For those who wonder, the sample command used here (to select a folder) is FOLDERBROWSE.EXE. I found it on the web site f2ko.de (http://f2ko.de/en/cmd.php).
If anyone has a better solution for that kind of commands accessible through a complex path, I will be very glad to hear of it.
Gilles
Just use the result from the FOR command. For example (inside a batch file):
for /F "delims=" %%I in ('dir /b /a-d /od FILESA*') do (echo %%I)
You can use the %%I as the value you want. Just like this: %%I.
And in advance the %%I does not have any spaces or CR characters and can be used for comparisons!!
If you're looking for the solution provided in Using the result of a command as an argument in bash?
then here is the code:
#echo off
if not "%1"=="" goto get_basename_pwd
for /f "delims=X" %%i in ('cd') do call %0 %%i
for /f "delims=X" %%i in ('dir /o:d /b') do echo %%i>>%filename%.txt
goto end
:get_basename_pwd
set filename=%~n1
:end
This will call itself with the result of the CD command, same as pwd.
String extraction on parameters will return the filename/folder.
Get the contents of this folder and append to the filename.txt
[Credits]: Thanks to all the other answers and some digging on the Windows XP commands page.
#echo off
ver | find "6.1." > nul
if %ERRORLEVEL% == 0 (
echo Win7
for /f "delims=" %%a in ('DIR "C:\Program Files\Microsoft Office\*Outlook.EXE" /B /P /S') do call set findoutlook=%%a
%findoutlook%
)
ver | find "5.1." > nul
if %ERRORLEVEL% == 0 (
echo WinXP
for /f "delims=" %%a in ('DIR "C:\Program Files\Microsoft Office\*Outlook.EXE" /B /P /S') do call set findoutlook=%%a
%findoutlook%
)
echo Outlook dir: %findoutlook%
"%findoutlook%"
You can capture all output in one variable, but the lines will be separated by a character of your choice (# in the example below) instead of an actual CR-LF.
#echo off
setlocal EnableDelayedExpansion
for /f "delims=" %%i in ('dir /b') do (
if "!DIR!"=="" (set DIR=%%i) else (set DIR=!DIR!#%%i)
)
echo directory contains:
echo %DIR%
Second version, if you need to print the contents out line-by-line. This takes advanted of the fact that there won't be duplicate lines of output from "dir /b", so it may not work in the general case.
#echo off
setlocal EnableDelayedExpansion
set count=0
for /f "delims=" %%i in ('dir /b') do (
if "!DIR!"=="" (set DIR=%%i) else (set DIR=!DIR!#%%i)
set /a count = !count! + 1
)
echo directory contains:
echo %DIR%
for /l %%c in (1,1,%count%) do (
for /f "delims=#" %%i in ("!DIR!") do (
echo %%i
set DIR=!DIR:%%i=!
)
)
#echo off
setlocal EnableDelayedExpansion
FOR /F "tokens=1 delims= " %%i IN ('echo hola') DO (
set TXT=%%i
)
echo 'TXT: %TXT%'
the result is 'TXT: hola'
You should use the for command, here is an example:
#echo off
rem Commands go here
exit /b
:output
for /f "tokens=* useback" %%a in (`%~1`) do set "output=%%a"
and you can use call :output "Command goes here" then the output will be in the %output% variable.
Note: If you have a command output that is multiline, this tool will set the output to the last line of your multiline command.
Please refer to this http://technet.microsoft.com/en-us/library/bb490982.aspx which explains what you can do with command output.

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