linux--watch命令使用

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更多发布于：2012-12-13 15:23

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	linux--watch命令使用 1.watch命令简介 www.atcpu.com watch [options] command The watch program executes a given command at regular inter-vals; the default is every two seconds. The command is passed to the shell (so be sure to quote or escape any special characters), and the results are displayed in a full-screen mode, so you can observe the output conveniently and see what has changed. For example, 每隔一段时间重复运行一个命令，默认间隔时间是2秒。要运行的命令直接传给shell（注意引用和转义特殊字符）。结果会展示为全屏模式，这样你可以很方便的观察改变。例如: watch -n 60 date executes the date command once a minute, sort of a poor man’s clock. Type ^C to exit. 执行date命令每分钟一次，输入^C 退出。 www.atcpu.com 2.Useful options 常用选项 -n seconds Set the time between executions, in seconds. 设置运行时间间隔，以秒为单位 -d Highlight differences in the output, to emphasize what has changed from one execution to the next. 高亮输出不同，强调两次执行的不同。 3.watch 手册 NAME watch - execute a program periodically, showing output fullscreen watch - 定期执行程序，输出全屏 SYNOPSIS watch [-dhvt] [-n <seconds>] [--differences[=cumulative]] [--help] [--interval=<seconds>] [--no-title] [--version] <command> DESCRIPTION watch runs command repeatedly, displaying its output (the first screen-full). This allows you to watch the program output change over time.By default, the program is run every 2 seconds; use -n or --interval to specify a different interval. 监视重复运行命令，展示输出（全屏）。让你监视程序输出变化。默认程序2s运行一次；使用-n或--interval 指定不同的间隔时间 The -d or --differences flag will highlight the differences between successive updates. The --differences[=cumulative] option makes highlighting "sticky", presenting a running display of all positions that have ever changed. The -t or --no-title option turns off the header showing the interval, command, and current time at the top of the display, as well as the following blank line. -d 或 --differences 会高亮显示新内容。--cumulative 选项让高亮保持，展示运行中所有的修改的内容。 -t 或 --no-title 选项关闭头部展示，只展示空白行。 watch will run until interrupted. watch会一直运行，知道中断。 NOTE Note that command is given to "sh -c" which means that you may need to use extra quoting to get the desired effect. 注意，命令"sh -c" 你需要应用起来才能达到预期的效果。 Note that POSIX option processing is used (i.e., option processing stops at the first non-option argument). This means that flags after command don’t get interpreted by watch itself. 注意，使用POSIX选项（选项会停在第一个非选项参数）意味着你不能在命令后再设置间隔。 www.atcpu.com EXAMPLES To watch for mail, you might do 查看邮件 watch -n 60 from To watch the contents of a directory change, you could use 查看目录变化： watch -d ls -l If you’re only interested in files owned by user joe, you might use 想找joe用户的文件，是下面的命令 watch -d ’ls -l \| fgrep joe’ To see the effects of quoting, try these out 看引号的使用 watch echo $$ watch echo ’$$’ watch echo "’"’$$’"’" 结束