blocks|key|1455583|text|exec不会在shell中执行命令|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1455584|试一试|1455585|Process+p+=+Runtime.getRuntime().exec(new+String[]{"csh","-c","cat+/home/narek/pk.txt"});|code-block|syntax|javascript|1455586|而不是。|1455587|我的系统上没有csh，所以我改用bash。下面的方法对我很有效|1455588|Process+p+=+Runtime.getRuntime().exec(new+String[]{"bash","-c","ls+/home/XXX"});|1455589|entityMap^0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|R|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|S|8|@]|9|@]|A|$G|H]]|$1|I|3|J|5|6|7|T|8|@]|9|@]|A|$]]|$1|K|3|L|5|6|7|U|8|@]|9|@]|A|$]]|$1|M|3|N|5|F|7|V|8|@]|9|@]|A|$G|H]]|$1|O|3|-4|5|6|7|W|8|@]|9|@]|A|$]]]|P|$]]

exec does not execute a command in your shell

try

<pre><code>Process p = Runtime.getRuntime().exec(new String[]{"csh","-c","cat /home/narek/pk.txt"});
</code></pre>

instead.

EDIT::
I don't have csh on my system so I used bash instead. The following worked for me

<pre><code>Process p = Runtime.getRuntime().exec(new String[]{"bash","-c","ls /home/XXX"});
</code></pre>

blocks|key|1455618|text|使用ProcessBuilder分隔命令和参数，而不是空格。无论使用什么shell，这都应该可以正常工作：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1455619|import+java.io.BufferedReader;
import+java.io.File;
import+java.io.IOException;
import+java.io.InputStreamReader;
import+java.util.ArrayList;
import+java.util.List;

public+class+Test+{

++++public+static+void+main(final+String[]+args)+throws+IOException,+InterruptedException+{
++++++++//Build+command+
++++++++List<String>+commands+=+new+ArrayList<String>();
++++++++commands.add("/bin/cat");
++++++++//Add+arguments
++++++++commands.add("/home/narek/pk.txt");
++++++++System.out.println(commands);

++++++++//Run+macro+on+target
++++++++ProcessBuilder+pb+=+new+ProcessBuilder(commands);
++++++++pb.directory(new+File("/home/narek"));
++++++++pb.redirectErrorStream(true);
++++++++Process+process+=+pb.start();

++++++++//Read+output
++++++++StringBuilder+out+=+new+StringBuilder();
++++++++BufferedReader+br+=+new+BufferedReader(new+InputStreamReader(process.getInputStream()));
++++++++String+line+=+null,+previous+=+null;
++++++++while+((line+=+br.readLine())+!=+null)
++++++++++++if+(!line.equals(previous))+{
++++++++++++++++previous+=+line;
++++++++++++++++out.append(line).append('\n');
++++++++++++++++System.out.println(line);
++++++++++++}

++++++++//Check+result
++++++++if+(process.waitFor()+==+0)+{
++++++++++++System.out.println("Success!");
++++++++++++System.exit(0);
++++++++}

++++++++//Abnormal+termination:+Log+command+parameters+and+output+and+throw+ExecutionException
++++++++System.err.println(commands);
++++++++System.err.println(out.toString());
++++++++System.exit(1);
++++}
}|code-block|syntax|javascript|1455620|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

Use ProcessBuilder to separate commands and arguments instead of spaces. This should work regardless of shell used:

<pre><code>import java.io.BufferedReader;
import java.io.File;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.List;

public class Test {

 public static void main(final String[] args) throws IOException, InterruptedException {
 //Build command 
 List&lt;String&gt; commands = new ArrayList&lt;String&gt;();
 commands.add("/bin/cat");
 //Add arguments
 commands.add("/home/narek/pk.txt");
 System.out.println(commands);

 //Run macro on target
 ProcessBuilder pb = new ProcessBuilder(commands);
 pb.directory(new File("/home/narek"));
 pb.redirectErrorStream(true);
 Process process = pb.start();

 //Read output
 StringBuilder out = new StringBuilder();
 BufferedReader br = new BufferedReader(new InputStreamReader(process.getInputStream()));
 String line = null, previous = null;
 while ((line = br.readLine()) != null)
 if (!line.equals(previous)) {
 previous = line;
 out.append(line).append('\n');
 System.out.println(line);
 }

 //Check result
 if (process.waitFor() == 0) {
 System.out.println("Success!");
 System.exit(0);
 }

 //Abnormal termination: Log command parameters and output and throw ExecutionException
 System.err.println(commands);
 System.err.println(out.toString());
 System.exit(1);
 }
}
</code></pre>

blocks|key|1240816|text|基于@Tim的示例构建一个自包含的方法：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1240817|import+java.io.BufferedReader;
import+java.io.File;
import+java.io.InputStreamReader;
import+java.util.ArrayList;

public+class+Shell+{

++++/**+Returns+null+if+it+failed+for+some+reason.
+++++*/
++++public+static+ArrayList<String>+command(final+String+cmdline,
++++final+String+directory)+{
++++++++try+{
++++++++++++Process+process+=+
++++++++++++++++new+ProcessBuilder(new+String[]+{"bash",+"-c",+cmdline})
++++++++++++++++++++.redirectErrorStream(true)
++++++++++++++++++++.directory(new+File(directory))
++++++++++++++++++++.start();

++++++++++++ArrayList<String>+output+=+new+ArrayList<String>();
++++++++++++BufferedReader+br+=+new+BufferedReader(
++++++++++++++++new+InputStreamReader(process.getInputStream()));
++++++++++++String+line+=+null;
++++++++++++while+(+(line+=+br.readLine())+!=+null+)
++++++++++++++++output.add(line);

++++++++++++//There+should+really+be+a+timeout+here.
++++++++++++if+(0+!=+process.waitFor())
++++++++++++++++return+null;

++++++++++++return+output;

++++++++}+catch+(Exception+e)+{
++++++++++++//Warning:+doing+this+is+no+good+in+high+quality+applications.
++++++++++++//Instead,+present+appropriate+error+messages+to+the+user.
++++++++++++//But+it's+perfectly+fine+for+prototyping.

++++++++++++return+null;
++++++++}
++++}

++++public+static+void+main(String[]+args)+{
++++++++test("which+bash");

++++++++test("find+.+-type+f+-printf+'%25T@\\\\t%25p\\\\n'+"
++++++++++++%2B+"%7C+sort+-n+%7C+cut+-f+2-+%7C+"
++++++++++++%2B+"sed+-e+'s/+/\\\\\\\\+/g'+%7C+xargs+ls+-halt");

++++}

++++static+void+test(String+cmdline)+{
++++++++ArrayList<String>+output+=+command(cmdline,+".");
++++++++if+(null+==+output)
++++++++++++System.out.println("\n\n\t\tCOMMAND+FAILED:+"+%2B+cmdline);
++++++++else
++++++++++++for+(String+line+:+output)
++++++++++++++++System.out.println(line);

++++}
}|code-block|syntax|javascript|1240818|(测试示例是command+that+lists+all+files+in+a+directory+and+its+subdirectories,+recursively,+in+chronological+order。)|offset|length|1240819|顺便说一句，如果有人能告诉我为什么我需要四个和八个反斜杠，而不是两个和四个，我就能学到一些东西。还有比我所计算的更多的无法逃脱的发生。|1240820|编辑:我刚刚在Linux上尝试了同样的代码，结果发现test命令中的反斜杠数量只有原来的一半！(即:预期数量为2和4。)现在它不再是奇怪的了，这是一个可移植性的问题。|1240821|entityMap|0|LINK|mutability|MUTABLE|url|https://superuser.com/a/745424/141883^0|0|0|6|2V|0|0|0|0^^$0|@$1|2|3|4|5|6|7|W|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|X|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|Y|8|@]|9|@$I|Z|J|10|1|11]]|A|$]]|$1|K|3|L|5|6|7|12|8|@]|9|@]|A|$]]|$1|M|3|N|5|6|7|13|8|@]|9|@]|A|$]]|$1|O|3|-4|5|6|7|14|8|@]|9|@]|A|$]]]|P|$Q|$5|R|S|T|A|$U|V]]]]

Building on @Tim's example to make a self-contained method:

<pre><code>import java.io.BufferedReader;
import java.io.File;
import java.io.InputStreamReader;
import java.util.ArrayList;

public class Shell {

 /** Returns null if it failed for some reason.
 */
 public static ArrayList&lt;String&gt; command(final String cmdline,
 final String directory) {
 try {
 Process process = 
 new ProcessBuilder(new String[] {"bash", "-c", cmdline})
 .redirectErrorStream(true)
 .directory(new File(directory))
 .start();

 ArrayList&lt;String&gt; output = new ArrayList&lt;String&gt;();
 BufferedReader br = new BufferedReader(
 new InputStreamReader(process.getInputStream()));
 String line = null;
 while ( (line = br.readLine()) != null )
 output.add(line);

 //There should really be a timeout here.
 if (0 != process.waitFor())
 return null;

 return output;

 } catch (Exception e) {
 //Warning: doing this is no good in high quality applications.
 //Instead, present appropriate error messages to the user.
 //But it's perfectly fine for prototyping.

 return null;
 }
 }

 public static void main(String[] args) {
 test("which bash");

 test("find . -type f -printf '%T@\\\\t%p\\\\n' "
 + "| sort -n | cut -f 2- | "
 + "sed -e 's/ /\\\\\\\\ /g' | xargs ls -halt");

 }

 static void test(String cmdline) {
 ArrayList&lt;String&gt; output = command(cmdline, ".");
 if (null == output)
 System.out.println("\n\n\t\tCOMMAND FAILED: " + cmdline);
 else
 for (String line : output)
 System.out.println(line);

 }
}
</code></pre>

(The test example is a <a href="https://superuser.com/a/745424/141883">command that lists all files in a directory and its subdirectories, recursively, in chronological order</a>.)

By the way, if somebody can tell me why I need four and eight backslashes there, instead of two and four, I can learn something. There is one more level of unescaping happening than what I am counting.

Edit: Just tried this same code on Linux, and there it turns out that I need half as many backslashes in the test command! (That is: the expected number of two and four.) Now it's no longer just weird, it's a portability problem.

I am trying to execute some Linux commands from Java using redirection (>&amp;) and pipes (|). How can Java invoke <code>csh</code> or <code>bash</code> commands?

I tried to use this:

<pre><code>Process p = Runtime.getRuntime().exec("shell command");
</code></pre>

But it's not compatible with redirections or pipes.

How to invoke a Linux shell command from Java

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

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我正在尝试使用重定向(>&)和管道(|)从Java执行一些Linux命令。Java如何调用csh或bash命令？我试着使用这个：Process p = Runtime.getRuntime().exec("shell command");但它与重定向或管道不兼容。

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