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Linux安装tailf

时间:2020-10-29 09:50:13      阅读:34      评论:0      收藏:0      [点我收藏+]

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  1. 新建文件tailf.c文件

    文件内容如下:

    /* tailf.c -- tail a log file and then follow it  
     * Created: Tue Jan  9 15:49:21 1996 by faith@acm.org  
     * Copyright 1996, 2003 Rickard E. Faith (faith@acm.org)  
     *  
     * Permission is hereby granted, free of charge, to any person obtaining a  
     * copy of this software and associated documentation files (the "Software"),  
     * to deal in the Software without restriction, including without limitation  
     * the rights to use, copy, modify, merge, publish, distribute, sublicense,  
     * and/or sell copies of the Software, and to permit persons to whom the  
     * Software is furnished to do so, subject to the following conditions:  
     *  
     * The above copyright notice and this permission notice shall be included  
     * in all copies or substantial portions of the Software.  
     *  
     * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR  
     * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,  
     * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL  
     * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR  
     * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,  
     * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR  
     * OTHER DEALINGS IN THE SOFTWARE.  
     *   
     * less -F and tail -f cause a disk access every five seconds.  This  
     * program avoids this problem by waiting for the file size to change.  
     * Hence, the file is not accessed, and the access time does not need to be  
     * flushed back to disk.  This is sort of a "stealth" tail.  
     */   
       
    #include <stdio.h>   
    #include <stdlib.h>   
    #include <unistd.h>   
    #include <malloc.h>   
    #include <sys/stat.h>   
    //#include "nls.h"   
    #define _(s) s   
       
    static size_t filesize(const char *filename)   
    {   
        struct stat sb;   
       
        if (!stat(filename, &sb)) return sb.st_size;   
        return 0;   
    }   
       
    static void tailf(const char *filename, int lines)   
    {   
        char **buffer;   
        int  head = 0;   
        int  tail = 0;   
        FILE *str;   
        int  i;   
       
        if (!(str = fopen(filename, "r"))) {   
        fprintf(stderr, _("Cannot open \"%s\" for read\n"), filename);   
        perror("");   
        exit(1);   
        }   
       
        buffer = malloc(lines * sizeof(*buffer));   
        for (i = 0; i < lines; i++) buffer[i] = malloc(BUFSIZ + 1);   
       
        while (fgets(buffer[tail], BUFSIZ, str)) {   
        if (++tail >= lines) {   
            tail = 0;   
            head = 1;   
        }   
        }   
       
        if (head) {   
        for (i = tail; i < lines; i++) fputs(buffer[i], stdout);   
        for (i = 0; i < tail; i++)     fputs(buffer[i], stdout);   
        } else {   
        for (i = head; i < tail; i++)  fputs(buffer[i], stdout);   
        }   
        fflush(stdout);   
       
        for (i = 0; i < lines; i++) free(buffer[i]);   
        free(buffer);   
    }   
       
    int main(int argc, char **argv)   
    {   
        char       buffer[BUFSIZ];   
        size_t     osize, nsize;   
        FILE       *str;   
        const char *filename;   
        int        count;   
       
        //setlocale(LC_ALL, "");   
        //bindtextdomain(PACKAGE, LOCALEDIR);   
        //textdomain(PACKAGE);   
       
        if (argc != 2) {   
        fprintf(stderr, _("Usage: tailf logfile\n"));   
        exit(1);   
        }   
       
        filename = argv[1];   
       
        tailf(filename, 10);   
       
        for (osize = filesize(filename);;) {   
        nsize = filesize(filename);   
        if (nsize != osize) {   
            if (!(str = fopen(filename, "r"))) {   
            fprintf(stderr, _("Cannot open \"%s\" for read\n"), filename);   
            perror(argv[0]);   
            exit(1);   
            }   
            if (!fseek(str, osize, SEEK_SET))   
                    while ((count = fread(buffer, 1, sizeof(buffer), str)) > 0)   
                        fwrite(buffer, 1, count, stdout);   
            fflush(stdout);   
            fclose(str);   
            osize = nsize;   
        }   
        usleep(250000);     /* 250mS */   
        }   
        return 0;   
    }   
    
  2. 安装

    gcc -Wall -o /usr/bin/tailf tailf.c
    

后续就可以直接使用tailf命令了

Linux安装tailf

标签:change   wal   strong   files   auth   lan   tailf   doc   fread   

原文地址:https://www.cnblogs.com/langkyeSir/p/13890739.html

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