How to feed a file into a program that reads stdin (on Windows command line)

command line

I have a program P that processes stdin. How can I feed a file into this program from the windows command line?

P < filename

does not work.

filename | P
filename > P

does not work either.

edit

tried again, in fact

P < filename

grep abc < lab.txt

does work. Thank you for the participation.

Best Answer

I tried this script that set the contents of the filename as variable "a" and then fed this variable "a" as an argument to the "p" program.

@echo off
for /f "tokens=1 delims={" %%a in ('TYPE filename ^| FINDstr /r "[a-z]"') do (cmd /c p "%%a")
pause

Note that this script has a number of limitations as I used regular expression in findstr command supposing that the contents of filename is just text. I don't know what your filename contents are so you have to modify it to suites your needs. Also you need to modify your program "p" so that it accepts arguments. Hope this help.

Related Solutions

Windows – Redirecting input from file to command-line program

You can automate interactive command line programs using expect

Here's an example (for telnet) from the Wikipedia article

# Assume $remote_server, $my_user_id, $my_password, and $my_command were read in earlier 
# in the script.
# Open a telnet session to a remote server, and wait for a username prompt.
spawn telnet $remote_server
expect "username:"
# Send the username, and then wait for a password prompt.
send "$my_user_id\r"
expect "password:"
# Send the password, and then wait for a shell prompt.
send "$my_password\r"
expect "%"
# Send the prebuilt command, and then wait for another shell prompt.
send "$my_command\r"
expect "%"
# Capture the results of the command into a variable. This can be displayed, or written to disk.
set results $expect_out(buffer)
# Exit the telnet session, and wait for a special end-of-file character.
send "exit\r"
expect eof

It should be clear that you can use this approach for your program as you know the prompt strings and you know what responses to feed it.

Windows – How to run .js file from a command line on windows

You have two options:

Cscript.exe "C:\Users\Public\TestPro\TestPro Automation Framework\taf.js"

Wscript.exe "C:\Users\Public\TestPro\TestPro Automation Framework\taf.js"

The former one starts the command line version of Windows Scripting Host and the latter one is starting the window version.

The command line options are documented here: https://docs.microsoft.com/en-us/windows-server/administration/windows-commands/cscript

and here: https://docs.microsoft.com/en-us/windows-server/administration/windows-commands/wscript

In your script file you should use the full path to your jar file and possibly full path to the java.exe

Alternatively, to allow the java.exe locate the tar-loader.jar file you should change the current directory to the one containing this file, so before invoking wscript make cd "C:\Users\Public\TestPro\TestPro Automation Framework\"

As you mentioned that you like to run this script in a single touch, you also may create a shortcut on your desktop that has a command line set to Wscript.exe "C:\Users\Public\TestPro\TestPro Automation Framework\taf.js" and working directory set to C:\Users\Public\TestPro\TestPro Automation Framework\

Best Answer

Related Solutions

Windows – Redirecting input from file to command-line program

Windows – How to run .js file from a command line on windows

Related Question