CODEWITHSUNDEEP
javaunix
Koray Tugay
Koray Tugay

Reputation: 23844

How can I specify folder for arguement to exec method in Java?

So I have this simple code:

Runtime rt = Runtime.getRuntime();
Process pr = rt.exec("ls");

which works fine. (pr input stream will give me the file names..)

However I want to make something like this work:

Process pr = rt.exec("~/ls");

I want to get the file names in the directory of the Home folder of the current logged in user.

What I get is:

Exception in thread "main" java.io.IOException: Cannot run program "~/ls": error=2, No such file or directory
at java.lang.ProcessBuilder.start(ProcessBuilder.java:1047)

Upvotes: 2

Views: 44

Answers (2)

Peter Lawrey
Peter Lawrey

Reputation: 533870

When you run a program, is is not the same as running a shell to parse your command line unless you actually call the shell 

exec("/bin/sh", "-c", "ls ~");

or

exec("ls", System.getProperty("user.home"));

Note: when you specify the directory at the start, you want to run the command in that directory, not pass the directory to a command as an argument.

e.g.

/bin/ls

means run the ls which is in the /bin directory (with no arguments)

ls /bin

mean pass /bin to the command ls

Upvotes: 2

Jonah Graham
Jonah Graham

Reputation: 7980

~ is an expansion handled by the shell, Java does not know about it.

To get the home directory use the java.home property (with System.getProperty)

Note if you want to run a program in a specific working directory, use ProcessBuilder and call the directory method.

Upvotes: 4

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