Linux head/tail命令详解程序员

head命令用于显示文件的开头的内容。在默认情况下，head命令显示文件的头10行内容。

tail命令用于显示文件的结尾的内容。在默认情况下，taild命令显示文件的后10行内容。

 -c, --bytes=[-]K print the first K bytes of each file; 

 with the leading `-, print all but the last 

 K bytes of each file 

 -n, --lines=[-]K print the first K lines instead of the first 10; 

 with the leading `-, print all but the last 

 K lines of each file 

 -q, --quiet, --silent never print headers giving file names 

 -v, --verbose always print headers giving file names 

 --help display this help and exit 

 --version output version information and exit

 -c, --bytes=K output the last K bytes; alternatively, use -c +K 

 to output bytes starting with the Kth of each file 

 -f, --follow[={name|descriptor}] 

 output appended data as the file grows; 

 -f, --follow, and --follow=descriptor are 

 equivalent 

 -F same as --follow=name --retry 

 -n, --lines=K output the last K lines, instead of the last 10; 

 or use -n +K to output lines starting with the Kth 

 --max-unchanged-stats=N 

 with --follow=name, reopen a FILE which has not 

 changed size after N (default 5) iterations 

 to see if it has been unlinked or renamed 

 (this is the usual case of rotated log files). 

 With inotify, this option is rarely useful. 

 --pid=PID with -f, terminate after process ID, PID dies 

 -q, --quiet, --silent never output headers giving file names 

 --retry keep trying to open a file even when it is or 

 becomes inaccessible; useful when following by 

 name, i.e., with --follow=name 

 -s, --sleep-interval=N with -f, sleep for approximately N seconds 

 (default 1.0) between iterations. 

 With inotify and --pid=P, check process P at 

 least once every N seconds. 

 -v, --verbose always output headers giving file names 

 --help display this help and exit 

 --version output version information and exit

head :显示文件的前几行,默认10行 

head -n 2 /home/omd/h.txt 

 == head -n 3 == head -3 可以直接跟行数 

cat h.txt | grep -v "hello" 过滤掉特定字符串，效率低，因为有管道 

 == grep -v "hello" h.txt 可以直接跟文件名，效率快 

tail: 显示文件最后几行，默认10行 

tail -10 /home/omd/h.txt 显示最后10行 

tail -f /home/omd/h.txt 实时跟踪文件， 如果文件不存在，则终止 

tail -F /home/omd/h.txt 如果文件不存在，会继续尝试 

head -30 /home/omd/h.txt | tail -11 /home/omd/h.txt 输出一个文件的20-30行显示文件的前n行 

head -n 5 log2014.log输出文件除了最后n行的全部内容 

head -n -6 log2014.log从第5行开始显示文件 

tail -n +5 log2014.log 【显示文件的全部内容】 

tail -n 5 log2014.log 【只显示最后的5行】 根more/less差不多 

原创文章，作者：Maggie-Hunter，如若转载，请注明出处：https://blog.ytso.com/2988.html