Executing a command

Question

I'm trying to execute a command:

public static void main(String[] args) { 
 int buffer;
 StringBuilder res = new StringBuilder();
 Process proc;
 try {
 proc = Runtime.getRuntime().exec("cat /proc/stat | grep 'btime' | awk '{print 2ドル}'");
 BufferedReader reader = new BufferedReader(new InputStreamReader(proc.getErrorStream()));
 String line;
 while ((line=reader.readLine())!=null) {
 System.out.println(line);
 }
 proc.waitFor();
 } catch (Exception e) {
 e.printStackTrace();
 }
}

But the result is not what I expected:

cat: '|': No such file or directory
cat: grep: No such file or directory
cat: "'btime'": No such file or directory
cat: '|': No such file or directory
cat: awk: No such file or directory
cat: ''\''{print': No such file or directory
cat: '2ドル}'\''': No such file or directory

What am I doing wrong? Ubuntu 18.04.

• Teddy: Runtime.exec cannot run arbitrary shell/terminal commands like this.
• Teddy: Possible duplicate of: stackoverflow.com/questions/15356405/…

Answer 1

Runtime.exec cannot run arbitrary shell/terminal commands like this.

You have to run the bash program and then send your command as parameter to bash. Bash will do the job for you.

https://stackoverflow.com/a/15356451/1364747

This is OS specific. On a different OS it might be a different command/terminal. Also you might need to know the path to that program.