Java execute command line and always replace when it asks [Y/N]

Question

I am calling java.lang.Runtime.exec(...) in my Java program to run a command, say:

ffmpeg -i input.mp4 output.mp4.

This is simply passed to my function to run:

    private static void RunCommand(String command) throws InterruptedException {
        try {
            // Execute command
            Process proc = Runtime.getRuntime().exec(command);
}
}

Everything is OK. But my question is to handle cases when the file already exists, so asks if it should replace it:

File 'output.avi' already exists. Overwrite ? [y/N]

What is the simplest way to ignore it (always assume y and replace)? Maybe through Java in code or FFMPEG command itself?

Through Java in code. Just implement it like that. Problem solved — Thomas Weller
– Thomas Weller, Commented Jul 26, 2017 at 20:17
hmm is not the problem of java, you need to check if there is flag for automatic yes of your command — Proxytype
– Proxytype, Commented Jul 26, 2017 at 20:17
@Proxytype You can delete the file in Java so there will not be a prompt — Thomas Weller
– Thomas Weller, Commented Jul 26, 2017 at 20:18
@ThomasWeller you just running command like you will done it from command line, if no automatic yes exists you will need to inject it to the process... as keystroke — Proxytype
– Proxytype, Commented Jul 26, 2017 at 20:22

llogan · Accepted Answer · 2017-07-26 20:46:25Z

1

Add -y as argument:

ffmpeg -y -i input.mp4 output.mp4

According to the documentation:

-y Overwrite output files without asking.
-n Do not overwrite output files, and exit immediately if a specified output file already exists.

edited Jul 26, 2017 at 20:46

llogan

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answered Jul 26, 2017 at 20:25

Proxytype

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6 Comments

user8071576 Over a year ago

Haha! Thanks. I have a question: there is a command which doesn't run in java, but when I copy the exact string and run in command line, it works?

user8071576 Over a year ago

ffmpeg -i "concat:/home/temp10.avi|/home/p2.avi|/home/temp15.avi" -c copy -y /home/output.avi

user8071576 Over a year ago

which is String c4="ffmpeg -i \"concat:"+dir+temp1+"|"+dir+ad+"|"+dir+temp3+"\" -c copy -y "+dir+output;

Proxytype Over a year ago

try to make more simple copy and see if it's works from java... try to listen to the stdio output for errors...

llogan Over a year ago

@Ariana That's a completely different issue. I recommend accepting this answer for the -y issue and asking a new question regarding the concat issue.

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