Java and unix

Question

I want to delete the old log files in log directory. To delete the log files which are more than 6 months, I have written the script like

find /dnbusr1/ghmil/BDELogs/import -type f -mtime +120 -exec rm -f {} \;

By using this script i can able to delete the old files. But how to invoke this script by using java? please any one help me...

Answer 1

Use java.lang.Runtime.exec() .

Answer 2

Using system calls in Java is possible, but is generally a bad idea because you'll lose the portability of the code. You could look into Ant and use something like this purge task.

Answer 3

This should help Java RunTime

Answer 4

Adding to Crashworks's answer, you call with these arguments in the cmdarray:

new String[] {"find", "/dnbusr1/ghmil/BDELogs/import", "-type", "f",
    "-mtime", "+120", "-exec", "rm", "-f", "{}", ";"}

If your find supports the -exec ... {} + syntax, change the ";" at the end to "+". It will make your command run faster (it will call rm on a batch of files at once, rather than once for each file).

Answer 5

If portability is an issue, preventing you from running with Runtime.exec(), this code is quite trivial to write in Java using File and a FilenameFilter.

Edit: Here is a static method to delete a directory tree... you can add in the filtering logic easily enough:

static public int deleteDirectory(File dir, boolean slf) {
    File[]                              dc;                                     // directory contents
    String                              dp;                                     // directory path
    int                                 oc=0;                                   // object count

    if(dir.exists()) {
        dir=dir.getAbsoluteFile();

        if(!dir.canWrite()) {
            throw new IoEscape(IoEscape.NOTAUT,"Not authorized to delete directory '"+dir+"'.");
            }

        dp=dir.getPath();
        if(dp.equals("/") || dp.equals("\\") || (dp.length()==3 && dp.charAt(1)==':' && (dp.charAt(2)=='/' || dp.charAt(2)=='\\'))) {
            // Prevent deletion of the root directory just as a basic restriction
            throw new IoEscape(IoEscape.GENERAL,"Cannot delete root directory '"+dp+"' using IoUtil.deleteDirectory().");
            }

        if((dc=dir.listFiles())!=null) {
            for(int xa=0; xa<dc.length; xa++) {
                if(dc[xa].isDirectory()) {
                    oc+=deleteDirectory(dc[xa]);
                    if(!dc[xa].delete()) { throw new IoEscape(IoEscape.GENERAL,"Unable to delete directory '"+dc[xa]+"' - it may not be empty, may be in use as a current directory, or may have restricted access."); }
                    }
                else {
                    if(!dc[xa].delete()) { throw new IoEscape(IoEscape.GENERAL,"Unable to delete file '"+dc[xa]+"' - it may be currently in use by a program, or have restricted access."); }
                    }
                oc++;
                }
            }

        if(slf) {
            if(!dir.delete()) { throw new IoEscape(IoEscape.GENERAL,"Unable to delete directory '"+dir+"' - it may not be empty, may be in use as a current directory, or may have restricted access."); }
            oc++;
            }
        }
    return oc;
    }

Answer 6

When you only want to call the command you described call:

Runtime r = Runtime.getRuntime();
Process process = r.exec("find /dnbusr1/ghmil/BDELogs/import -type f -mtime +120 -exec rm -f {} \\;"); //$NON-NLS-1$
process.waitFor();

If you want to call more than one command use Chris Jester-Young answer. The exec method can also define files you want to use. The other answers link the method describtion.