Question

我有一个shell脚本，它将输出发送到控制台

ID=$PPID
echo the process id of the parent of this script is $ID

#fetch the parent of the program which executed this shell
read PID < <(exec ps -o ppid= "$ID")
echo the grand parent id of the script is $PID

read GPID < <(exec ps -o ppid= "$PID")
echo the grand parent id of the script is $GPID


while read -u 4 P; do
 top -c -n 1 -p "$P"
done 4< <(exec pgrep -P "$PID") >&1

我从java程序调用此脚本并尝试在控制台上显示输出，但只显示echo的输出。 top命令的输出没有出现在java控制台上。

这是我的java程序

import java.io.BufferedReader;

public class InformationFetcher {

    public InformationFetcher() {
    }

    public static void main(String[] args) {
    InformationFetcher informationFetcher = new InformationFetcher();
    try {
        Process process = Runtime.getRuntime().exec(
            informationFetcher.getFilePath());
        InputStream in = process.getInputStream();
        printInputStream(in);
    } catch (IOException e) {
        e.printStackTrace();
    }

    }

    private static void printInputStream(InputStream in) throws IOException {
    BufferedReader reader = new BufferedReader(new InputStreamReader(in));
    StringBuffer outBuffer = new StringBuffer();
    String newLine = System.getProperty("line.separator");
    String line;
    while ((line = reader.readLine()) != null) {
        outBuffer.append(line);
        outBuffer.append(newLine);
    }
    System.out.println(outBuffer.toString());
    }

    public String getFilePath() {
    return this.getClass().getResource("/idFetcher.sh").getPath();
    }

}

输出

the process id of the parent of this script is 3721
the grand parent id of the script is 3241
the grand parent id of the script is 3240

但它也应该显示top命令的输出。任何帮助将不胜感激。

Answer 1

我对top输出的方式不太确定，但似乎top没有以正常方式将结果发送到STDOUT。< / p>

但是，如果您希望top以正常方式将结果发送到STDOUT，请为其指定-b：

top -b -n 1
# -b means in batch mode, which outputs to `STDOUT` normally

如何将shell脚本输出重定向到java控制台

1 个答案: