blocks|key|1058232|text|您可以使用shell循环模拟基本功能：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1058233|while+:;+do+clear;+your_command;+sleep+2;+done|code-block|syntax|javascript|1058234|这将永远循环，清除屏幕，运行您的命令，并等待两秒钟-基本的watch+your_command实现。|offset|length|style|CODE|1058235|您可以更进一步，创建一个可以接受your_command和sleep_duration作为参数的watch.sh脚本：|1058236|#!/bin/bash
#+usage:+watch.sh+<your_command>+<sleep_duration>

while+:;+
++do+
++clear
++date
++$1
++sleep+$2
done|1058237|entityMap^0|0|0|T|I|0|G|C|T|E|1C|8|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|T|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|U|8|@$I|V|J|W|K|L]]|9|@]|A|$]]|$1|M|3|N|5|6|7|X|8|@$I|Y|J|Z|K|L]|$I|10|J|11|K|L]|$I|12|J|13|K|L]]|9|@]|A|$]]|$1|O|3|P|5|D|7|14|8|@]|9|@]|A|$E|F]]|$1|Q|3|-4|5|6|7|15|8|@]|9|@]|A|$]]]|R|$]]

You can emulate the basic functionality with the shell loop:

<pre><code>while :; do clear; your_command; sleep 2; done
</code></pre>

That will loop forever, clear the screen, run your command, and wait two seconds - the basic <code>watch your_command</code> implementation.

You can take this a step further and create a <code>watch.sh</code> script that can accept <code>your_command</code> and <code>sleep_duration</code> as parameters:

<pre><code>#!/bin/bash
# usage: watch.sh &lt;your_command&gt; &lt;sleep_duration&gt;

while :; 
 do 
 clear
 date
 $1
 sleep $2
done
</code></pre>

blocks|key|5096225|text|安装了Homebrew后：|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|5096226|brew+install+watch|style|CODE|5096227|entityMap|0|LINK|mutability|MUTABLE|url|http://brew.sh/^0|3|8|0|0|0|I|0^^$0|@$1|2|3|4|5|6|7|P|8|@]|9|@$A|Q|B|R|1|S]]|C|$]]|$1|D|3|E|5|6|7|T|8|@$A|U|B|V|F|G]]|9|@]|C|$]]|$1|H|3|-4|5|6|7|W|8|@]|9|@]|C|$]]]|I|$J|$5|K|L|M|C|$N|O]]]]

With <a href="http://brew.sh/">Homebrew</a> installed:

<code>brew install watch</code>

blocks|key|1775752|text|使用MacPorts|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|1775753|$+sudo+port+install+watch|code-block|syntax|javascript|1775754|entityMap|0|LINK|mutability|MUTABLE|url|http://www.macports.org/^0|2|8|0|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@$A|R|B|S|1|T]]|C|$]]|$1|D|3|E|5|F|7|U|8|@]|9|@]|C|$G|H]]|$1|I|3|-4|5|6|7|V|8|@]|9|@]|C|$]]]|J|$K|$5|L|M|N|C|$O|P]]]]

Use <a href="http://www.macports.org/" rel="nofollow noreferrer">MacPorts</a>:
<pre><code>$ sudo port install watch
</code></pre>

blocks|key|760455|text|上面的shell可以做到这一点，您甚至可以将它们转换为别名(您可能需要包装在一个函数中来处理参数)：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|760456|alias+myWatch='_()+{+while+:;+do+clear;+$2;+sleep+$1;+done+};+_'|code-block|syntax|javascript|760457|示例：|760458|myWatch+1+ls+##+Self-explanatory
myWatch+5+"ls+-lF+$HOME"+##+Every+5+seconds,+list+out+home+directory;+double-quotes+around+command+to+keep+its+arguments+together|760459|或者，Homebrew可以从http://procps.sourceforge.net/安装手表|offset|length|760460|brew+install+watch|760461|entityMap|0|LINK|mutability|MUTABLE|url|https://en.wikipedia.org/wiki/Homebrew_%2528package_management_software%2529|1|http://procps.sourceforge.net/^0|0|0|0|0|3|8|0|E|U|1|0|0^^$0|@$1|2|3|4|5|6|7|10|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|11|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|12|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|13|8|@]|9|@]|A|$E|F]]|$1|K|3|L|5|6|7|14|8|@]|9|@$M|15|N|16|1|17]|$M|18|N|19|1|1A]]|A|$]]|$1|O|3|P|5|D|7|1B|8|@]|9|@]|A|$E|F]]|$1|Q|3|-4|5|6|7|1C|8|@]|9|@]|A|$]]]|R|$S|$5|T|U|V|A|$W|X]]|Y|$5|T|U|V|A|$W|Z]]]]

The shells above will do the trick, and you could even convert them to an alias (you may need to wrap in a function to handle parameters):
<pre><code>alias myWatch='_() { while :; do clear; $2; sleep $1; done }; _'
</code></pre>
Examples:
<pre><code>myWatch 1 ls ## Self-explanatory
myWatch 5 &quot;ls -lF $HOME&quot; ## Every 5 seconds, list out home directory; double-quotes around command to keep its arguments together
</code></pre>
Alternately, <a href="https://en.wikipedia.org/wiki/Homebrew_%28package_management_software%29" rel="nofollow noreferrer">Homebrew</a> can install the watch from <a href="http://procps.sourceforge.net/" rel="nofollow noreferrer">http://procps.sourceforge.net/</a>:
<pre><code>brew install watch
</code></pre>

blocks|key|1775736|text|也许“看”不是你想要的。您可能希望寻求帮助来解决您的问题，而不是实现您的解决方案！:)|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1775737|如果您的真正目标是基于从tail命令中看到的内容来触发操作，那么您可以将其作为尾部本身的一部分来实现。您可以按需运行代码，而不是像watch那样“定期”运行。|offset|length|style|CODE|1775738|#!/bin/sh

tail+-F+/var/log/somelogfile+%7C+while+read+line;+do
++if+echo+"$line"+%7C+grep+-q+'[Ss]ome.regex';+then
++++#+do+your+stuff
++fi
done|code-block|syntax|javascript|1775739|请注意，tail+-F将继续跟踪日志文件，即使它被newsyslog或logrotate轮换。您希望使用它而不是小写的tail+-f。有关详细信息，请查看man+tail。|1775740|也就是说，如果您确实希望定期运行命令，可以将提供的其他答案转换为简短的shell脚本：|1775741|#!/bin/sh
if+[+-z+"$2"+];+then
++echo+"Usage:+$0+SECONDS+COMMAND"+>&2
++exit+1
fi

SECONDS=$1
shift+1
while+sleep+$SECONDS;+do
++clear
++$*
done|1775742|entityMap^0|0|C|4|1T|5|0|0|4|7|1N|7|25|8|0|0|0^^$0|@$1|2|3|4|5|6|7|U|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|V|8|@$D|W|E|X|F|G]|$D|Y|E|Z|F|G]]|9|@]|A|$]]|$1|H|3|I|5|J|7|10|8|@]|9|@]|A|$K|L]]|$1|M|3|N|5|6|7|11|8|@$D|12|E|13|F|G]|$D|14|E|15|F|G]|$D|16|E|17|F|G]]|9|@]|A|$]]|$1|O|3|P|5|6|7|18|8|@]|9|@]|A|$]]|$1|Q|3|R|5|J|7|19|8|@]|9|@]|A|$K|L]]|$1|S|3|-4|5|6|7|1A|8|@]|9|@]|A|$]]]|T|$]]

It may be that "watch" is not what you want. You probably want to ask for help in solving your problem, not in implementing your solution! :)

If your real goal is to trigger actions based on what's seen from the <code>tail</code> command, then you can do that as part of the tail itself. Instead of running "periodically", which is what <code>watch</code> does, you can run your code on demand.

<pre><code>#!/bin/sh

tail -F /var/log/somelogfile | while read line; do
 if echo "$line" | grep -q '[Ss]ome.regex'; then
 # do your stuff
 fi
done
</code></pre>

Note that <code>tail -F</code> will continue to follow a log file even if it gets rotated by newsyslog or logrotate. You want to use this instead of the lower-case <code>tail -f</code>. Check <code>man tail</code> for details.

That said, if you really do want to run a command periodically, the other answers provided can be turned into a short shell script:

<pre><code>#!/bin/sh
if [ -z "$2" ]; then
 echo "Usage: $0 SECONDS COMMAND" &gt;&amp;2
 exit 1
fi

SECONDS=$1
shift 1
while sleep $SECONDS; do
 clear
 $*
done
</code></pre>

blocks|key|760452|text|我将采用here的答案|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|760453|bash+-c+'while+[+0+];+do+<your+command>;+sleep+5;+done'|code-block|syntax|javascript|760454|但你最好还是用installing+watch，因为这不是很干净...|760455|entityMap|0|LINK|mutability|MUTABLE|url|https://unix.stackexchange.com/questions/10646/repeat-a-unix-command-every-x-seconds-forever/28859#28859|1|http://osxdaily.com/2010/08/22/install-watch-command-on-os-x/^0|4|4|0|0|0|7|G|1|0^^$0|@$1|2|3|4|5|6|7|U|8|@]|9|@$A|V|B|W|1|X]]|C|$]]|$1|D|3|E|5|F|7|Y|8|@]|9|@]|C|$G|H]]|$1|I|3|J|5|6|7|Z|8|@]|9|@$A|10|B|11|1|12]]|C|$]]|$1|K|3|-4|5|6|7|13|8|@]|9|@]|C|$]]]|L|$M|$5|N|O|P|C|$Q|R]]|S|$5|N|O|P|C|$Q|T]]]]

I am going with the answer from <a href="https://unix.stackexchange.com/questions/10646/repeat-a-unix-command-every-x-seconds-forever/28859#28859">here</a>:
<pre><code>bash -c 'while [ 0 ]; do &lt;your command&gt;; sleep 5; done'
</code></pre>
But you're really better off <a href="http://osxdaily.com/2010/08/22/install-watch-command-on-os-x/" rel="nofollow noreferrer">installing watch</a> as this isn't very clean...

blocks|key|5096336|text|如果watch不想通过|type|unstyled|depth|inlineStyleRanges|entityRanges|data|5096337|brew+install+watch|code-block|syntax|javascript|5096338|还有另一个类似的/复制版本，它安装并完美地工作在我身上|5096339|brew+install+visionmedia-watch|5096340|https://github.com/tj/watch|offset|length|5096341|entityMap|0|LINK|mutability|MUTABLE|url^0|0|0|0|0|0|R|0|0^^$0|@$1|2|3|4|5|6|7|V|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|W|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|X|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|Y|8|@]|9|@]|A|$E|F]]|$1|K|3|L|5|6|7|Z|8|@]|9|@$M|10|N|11|1|12]]|A|$]]|$1|O|3|-4|5|6|7|13|8|@]|9|@]|A|$]]]|P|$Q|$5|R|S|T|A|$U|L]]]]

If watch doesn't want to install via 

<pre><code>brew install watch
</code></pre>

There is another similar/copy version that installed and worked perfectly for me

<pre><code>brew install visionmedia-watch
</code></pre>

<a href="https://github.com/tj/watch" rel="noreferrer">https://github.com/tj/watch</a>

blocks|key|5096197|text|或者，在~/.bashrc文件中：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|5096198|function+watch+{
++++while+:;+do+clear;+date;+echo;+$@;+sleep+2;+done
}|code-block|syntax|javascript|5096199|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

Or, in your ~/.bashrc file:
<pre><code>function watch {
 while :; do clear; date; echo; $@; sleep 2; done
}
</code></pre>

blocks|key|1781606|text|为了防止主命令在可察觉的时间内完成时出现闪烁，您可以捕获输出并在完成时仅清除屏幕。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1781607|function+watch+{while+:;+do+a=$($@);+clear;+echo+"$(date)\n\n$a";+sleep+1;++done}|code-block|syntax|javascript|1781608|然后通过以下方式使用它：|1781609|watch+istats|1781610|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|N|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|O|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|K|3|-4|5|6|7|Q|8|@]|9|@]|A|$]]]|L|$]]

To prevent flickering when your main command takes perceivable time to complete, you can capture the output and only clear screen when it's done.
<pre><code>function watch {while :; do a=$($@); clear; echo &quot;$(date)\n\n$a&quot;; sleep 1; done}
</code></pre>
Then use it by:
<pre><code>watch istats
</code></pre>

blocks|key|5096304|text|试试这个：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|5096305|#!/bin/bash
#+usage:+watch+[-n+integer]+COMMAND

case+$#+in
++++0)
++++++++echo+"Usage+$0+[-n+int]+COMMAND"
++++++++;;
++++*)++++++
++++++++sleep=2;
++++++++;;
esac++++

if+[+"$1"+==+"-n"+];+then
++++sleep=$2
++++shift;+shift
fi


while+:;+
++++do+
++++clear;+
++++echo+"$(date)+every+${sleep}s+$@";+echo+
++++$@;+
++++sleep+$sleep;+
done|code-block|syntax|javascript|5096306|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

Try this:

<pre><code>#!/bin/bash
# usage: watch [-n integer] COMMAND

case $# in
 0)
 echo "Usage $0 [-n int] COMMAND"
 ;;
 *) 
 sleep=2;
 ;;
esac 

if [ "$1" == "-n" ]; then
 sleep=$2
 shift; shift
fi


while :; 
 do 
 clear; 
 echo "$(date) every ${sleep}s $@"; echo 
 $@; 
 sleep $sleep; 
done
</code></pre>

blocks|key|760543|text|下面是一个略微更改过的of+this+answer版本：|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|760544|760545|检查有效参数|unordered-list-item|760546|在顶部显示日期和持续时间标题|760547|将"+duration“参数移动为第一个参数，因此可以轻松地将复杂命令作为其余参数进行传递。|760548|760549|要使用它：|760550|760551|通过运行watch+1+echo+"hi+there"|style|CODE|760552|将其保存到终端中的chmod+700+~/bin/watch，使其对其执行executable.|760553|try操作|760554|760555|~/bin/观看|BOLD|760556|#!/bin/bash

function+show_help()
{
++echo+""
++echo+"usage:+watch+[sleep+duration+in+seconds]+[command]"
++echo+""
++echo+"e.g.+To+cat+a+file+every+second,+run+the+following"
++echo+""
++echo+"+++++watch+1+cat+/tmp/it.txt"+
++exit;
}

function+show_help_if_required()
{
++if+[+"$1"+==+"help"+]
++then
++++++show_help
++fi
++if+[+-z+"$1"+]
++++then
++++++show_help
++fi
}

function+require_numeric_value()
{
++REG_EX='%5E[0-9]%2B$'
++if+!+[[+$1+=~+$REG_EX+]]+;+then
++++show_help
++fi
}

show_help_if_required+$1
require_numeric_value+$1

DURATION=$1
shift

while+:;+do+
++clear
++echo+"Updating+every+$DURATION+seconds.+Last+updated+$(date)"
++bash+-c+"$*"
++sleep+$DURATION
done|code-block|syntax|javascript|760557|entityMap|0|LINK|mutability|MUTABLE|url|https://stackoverflow.com/questions/9574089/osx-bash-watch-command/9574123#9574123^0|B|E|0|0|0|0|0|0|0|0|0|4|N|0|9|L|0|0|0|0|8|0|0^^$0|@$1|2|3|4|5|6|7|1E|8|@]|9|@$A|1F|B|1G|1|1H]]|C|$]]|$1|D|3|-4|5|6|7|1I|8|@]|9|@]|C|$]]|$1|E|3|F|5|G|7|1J|8|@]|9|@]|C|$]]|$1|H|3|I|5|G|7|1K|8|@]|9|@]|C|$]]|$1|J|3|K|5|G|7|1L|8|@]|9|@]|C|$]]|$1|L|3|-4|5|6|7|1M|8|@]|9|@]|C|$]]|$1|M|3|N|5|6|7|1N|8|@]|9|@]|C|$]]|$1|O|3|-4|5|6|7|1O|8|@]|9|@]|C|$]]|$1|P|3|Q|5|G|7|1P|8|@$A|1Q|B|1R|R|S]]|9|@]|C|$]]|$1|T|3|U|5|6|7|1S|8|@$A|1T|B|1U|R|S]]|9|@]|C|$]]|$1|V|3|W|5|G|7|1V|8|@]|9|@]|C|$]]|$1|X|3|-4|5|6|7|1W|8|@]|9|@]|C|$]]|$1|Y|3|Z|5|6|7|1X|8|@$A|1Y|B|1Z|R|10]]|9|@]|C|$]]|$1|11|3|12|5|13|7|20|8|@]|9|@]|C|$14|15]]|$1|16|3|-4|5|6|7|21|8|@]|9|@]|C|$]]]|17|$18|$5|19|1A|1B|C|$1C|1D]]]]

Here's a slightly changed version <a href="https://stackoverflow.com/questions/9574089/osx-bash-watch-command/9574123#9574123">of this answer</a> that:

<ul>
<li>checks for valid args</li>
<li>shows a date and duration title at the top</li>
<li>moves the "duration" argument to be the 1st argument, so complex commands can be easily passed as the remaining arguments.</li>
</ul>

To use it:

<ul>
<li>Save this to <code>~/bin/watch</code></li>
<li>execute <code>chmod 700 ~/bin/watch</code> in a terminal to make it executable.</li>
<li>try it by running <code>watch 1 echo "hi there"</code></li>
</ul>

~/bin/watch

<pre><code>#!/bin/bash

function show_help()
{
 echo ""
 echo "usage: watch [sleep duration in seconds] [command]"
 echo ""
 echo "e.g. To cat a file every second, run the following"
 echo ""
 echo " watch 1 cat /tmp/it.txt" 
 exit;
}

function show_help_if_required()
{
 if [ "$1" == "help" ]
 then
 show_help
 fi
 if [ -z "$1" ]
 then
 show_help
 fi
}

function require_numeric_value()
{
 REG_EX='^[0-9]+$'
 if ! [[ $1 =~ $REG_EX ]] ; then
 show_help
 fi
}

show_help_if_required $1
require_numeric_value $1

DURATION=$1
shift

while :; do 
 clear
 echo "Updating every $DURATION seconds. Last updated $(date)"
 bash -c "$*"
 sleep $DURATION
done
</code></pre>

blocks|key|1781640|text|使用Nix包管理器！|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|1781641|安装Nix，然后执行nix-env+-iA+nixpkgs.watch，在完成安装说明(包括在shell中获取.+"$HOME/.nix-profile/etc/profile.d/nix.sh"+)后，应该可以使用它。|style|CODE|1781642|entityMap|0|LINK|mutability|MUTABLE|url|https://nixos.org/nix/download.html^0|2|3|0|0|A|P|1J|17|0^^$0|@$1|2|3|4|5|6|7|P|8|@]|9|@$A|Q|B|R|1|S]]|C|$]]|$1|D|3|E|5|6|7|T|8|@$A|U|B|V|F|G]|$A|W|B|X|F|G]]|9|@]|C|$]]|$1|H|3|-4|5|6|7|Y|8|@]|9|@]|C|$]]]|I|$J|$5|K|L|M|C|$N|O]]]]

Use the <a href="https://nixos.org/nix/download.html" rel="nofollow noreferrer">Nix</a> package manager!
Install Nix, and then do <code>nix-env -iA nixpkgs.watch</code> and it should be available for use after the completing the install instructions (including sourcing <code>. &quot;$HOME/.nix-profile/etc/profile.d/nix.sh&quot;</code> in your shell).

I'm looking for the best way to duplicate the Linux 'watch' command on Mac OS X. I'd like to run a command every few seconds to pattern match on the contents of an output file using 'tail' and 'sed'.
What's my best option on a Mac, and can it be done without downloading software?

OS X Bash, 'watch' command

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

文章

问答

视频

学习中心

腾讯云实验室

直播

竞赛

腾讯云代码分析专区

腾讯iOA零信任安全管理系统专区

腾讯云架构师技术同盟交流圈

腾讯云数据库专区

腾讯云顾问专区

腾讯云原生专区

腾讯混元专区

腾讯云TCE专区

腾讯云Lighthouse专区

腾讯云HAI专区

腾讯云Edgeone专区

腾讯云存储专区

腾讯云智能专区

腾讯轻联专区 

腾讯云开发专区

TAPD专区

腾讯轻量云游戏服专区

腾讯云最具价值专家

腾讯云架构师技术同盟

腾讯云创作之星

腾讯云开发者先锋

腾讯云代码助手

云原生构建

TAPD 敏捷项目管理

Cloud Studio

SDK中心

API中心

命令行工具

涵盖代码开发、场景应用、自动测试全流程，助你从零构建专属AI助手

一站式MCP教程库，解锁AI应用新玩法

我正在寻找在Mac OS X上复制Linux 'watch‘命令的最佳方法。我想每隔几秒钟运行一次命令，以便使用'tail’和'sed‘对输出文件的内容进行模式匹配。我在Mac上最好的选择是什么，不下载软件就能做到吗？

问OS X Bash，'watch‘命令
EN

回答 12

Stack Overflow用户

Stack Overflow用户

Stack Overflow用户

社区

活动

圈层

关于

腾讯云开发者

热门产品

热门推荐

更多推荐

问OS X Bash，'watch‘命令EN

回答 12

Stack Overflow用户

Stack Overflow用户

Stack Overflow用户

社区

活动

圈层

关于

腾讯云开发者

热门产品

热门推荐

更多推荐

问OS X Bash，'watch‘命令
EN