将DOS中程序的stdout导出到每日滚动日志文件?

如果不控制正在运行的程序的源代码,一种可能是使用另一个脚本,作为计划任务运行,关闭程序,移动日志文件,然后重新启动程序。把这个安排在午夜左右。

如果你 不能 定期关闭程序,另一种可能性是开发一个过滤程序,它将采用标准输入,并根据今天的日期将其发送到日志文件。该程序可以检测日期更改,并在文件超过午夜边界时关闭/重新打开文件。

然后将原始程序的输出通过这个过滤器进行传输。顺便说一下,这是真管道。您当前所做的不是技术上的管道而是重定向(管道指向进程,重定向指向文件)。

伪代码是这样的:

lastDate = ""
currFile = null
while not end of file on standard input:
    get line from standard input
    currDate = getDate()
    if currDate not equal to lastDate:
        if currFile not null:
            close currFile
        currFile = open("prefix_"+currDate+".log")
    write line to currFile
if currFile not null:
    close currFile
exit

作为概念的证明,这里有一个脚本( qqtest.sh )它运行,每13秒生成一次日期,十次:

#!/usr/bin/bash
for i in 0 1 2 3 4 5 6 7 8 9 ; do
    echo $i $(date)
    sleep 13
done

这里有一个C过滤器程序( qq.c )这就是我在上面的回答中所描述的:

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <time.h>

static char *getDate (void) {
    static char tbuff[sizeof("yyyymmddhhmm")]; // "yyyymmdd" for date.
    time_t now = time (0);
    struct tm *tm = localtime (&now);
    strftime (tbuff, 100, "%Y%m%d%H%M", tm);   // "%Y%m%d" for date.
    return tbuff;
}

int main (void) {
    int ch, lastCh = '\n';
    FILE *fOut = NULL;
    char *currDate, *lastDate = strdup ("");
    char fspec[1000];

    // Just process characters until finished.

    while ((ch = fgetc (stdin)) != EOF) {
        // Only switch logs if first character of a line.

        if (lastCh == '\n') {
            // Has date changed?

            currDate = getDate();
            if (strcmp (currDate, lastDate) != 0) {
                // Yes, close old file if there was one.

                if (fOut != NULL)
                    fclose (fOut);

                // Then store new date and open new file.

                free (lastDate);
                lastDate = strdup (currDate);
                sprintf (fspec, "qqfile_%s.log", lastDate);
                fOut = fopen (fspec, "w");
            }
        }

        // Output character to current file then save.

        fputc (ch, fOut);
        lastCh = ch;
    }

    // Clean up memory and file handles, then exit.

    free (lastDate);
    if (fOut != NULL)
        fclose (fOut);

    return 0;
}

执行时:

./qqtest.sh | ./qq

它创建以下文件。

$ cat qqfile_201005211146.log
0 Fri May 21 11:46:40 WAST 2010
1 Fri May 21 11:46:53 WAST 2010

$ cat qqfile_201005211147.log
2 Fri May 21 11:47:06 WAST 2010
3 Fri May 21 11:47:19 WAST 2010
4 Fri May 21 11:47:33 WAST 2010
5 Fri May 21 11:47:46 WAST 2010
6 Fri May 21 11:47:59 WAST 2010

$ cat qqfile_201005211148.log
7 Fri May 21 11:48:12 WAST 2010
8 Fri May 21 11:48:25 WAST 2010
9 Fri May 21 11:48:38 WAST 2010

注意,这使用一个分钟边界来切换日志文件。改变 getDate 函数使用日边界(请参见注释)。