blocks|key|720264|text|可以添加到crontab中，如下所示：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|720265|#write+out+current+crontab
crontab+-l+>+mycron
#echo+new+cron+into+cron+file
echo+"00+09+*+*+1-5+echo+hello"+>>+mycron
#install+new+cron+file
crontab+mycron
rm+mycron|code-block|syntax|javascript|720266|Cron线解释|720267|*+*+*+*+*+"command+to+be+executed"
-+-+-+-+-
%7C+%7C+%7C+%7C+%7C
%7C+%7C+%7C+%7C+-----+Day+of+week+(0+-+7)+(Sunday=0+or+7)
%7C+%7C+%7C+-------+Month+(1+-+12)
%7C+%7C+---------+Day+of+month+(1+-+31)
%7C+-----------+Hour+(0+-+23)
-------------+Minute+(0+-+59)|720268|源nixCraft.|offset|length|720269|entityMap|0|LINK|mutability|MUTABLE|url|http://www.cyberciti.biz/faq/how-do-i-add-jobs-to-cron-under-linux-or-unix-oses/^0|0|0|0|0|1|8|0|0^^$0|@$1|2|3|4|5|6|7|W|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|X|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|Y|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|Z|8|@]|9|@]|A|$E|F]]|$1|K|3|L|5|6|7|10|8|@]|9|@$M|11|N|12|1|13]]|A|$]]|$1|O|3|-4|5|6|7|14|8|@]|9|@]|A|$]]]|P|$Q|$5|R|S|T|A|$U|V]]]]

You can add to the crontab as follows:

<pre><code>#write out current crontab
crontab -l &gt; mycron
#echo new cron into cron file
echo "00 09 * * 1-5 echo hello" &gt;&gt; mycron
#install new cron file
crontab mycron
rm mycron
</code></pre>

<hr>

<h2>Cron line explaination</h2>

<pre><code>* * * * * "command to be executed"
- - - - -
| | | | |
| | | | ----- Day of week (0 - 7) (Sunday=0 or 7)
| | | ------- Month (1 - 12)
| | --------- Day of month (1 - 31)
| ----------- Hour (0 - 23)
------------- Minute (0 - 59)
</code></pre>

Source <a href="http://www.cyberciti.biz/faq/how-do-i-add-jobs-to-cron-under-linux-or-unix-oses/" rel="noreferrer">nixCraft</a>.

blocks|key|720274|text|编辑(固定覆盖)：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|720275|cat+<(crontab+-l)+<(echo+"1+2+3+4+5+scripty.sh")+%7C+crontab+-|code-block|syntax|javascript|720276|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|$]]

EDIT (fixed overwriting):

<pre><code>cat &lt;(crontab -l) &lt;(echo "1 2 3 4 5 scripty.sh") | crontab -
</code></pre>

blocks|key|720315|text|不，crontab中没有修改cron文件的选项。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|720316|您必须:接受当前cron文件(crontab+-l+>+newfile)，修改它并将新文件放置到位(crontab新文件)。|720317|如果您熟悉perl，可以使用此模块Config::Crontab。|offset|length|720318|安德里亚|720319|entityMap|0|LINK|mutability|MUTABLE|url|http://search.cpan.org/dist/Config-Crontab/Crontab.pm^0|0|0|H|F|0|0|0^^$0|@$1|2|3|4|5|6|7|R|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|S|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|T|8|@]|9|@$F|U|G|V|1|W]]|A|$]]|$1|H|3|I|5|6|7|X|8|@]|9|@]|A|$]]|$1|J|3|-4|5|6|7|Y|8|@]|9|@]|A|$]]]|K|$L|$5|M|N|O|A|$P|Q]]]]

No, there is no option in crontab to modify the cron files.

You have to: take the current cron file (crontab -l > newfile), change it and put the new file in place (crontab newfile).

If you are familiar with perl, you can use this module <a href="http://search.cpan.org/dist/Config-Crontab/Crontab.pm" rel="nofollow noreferrer" title="Config::Crontab">Config::Crontab</a>.

LLP, Andrea

blocks|key|892417|text|你也许能在飞行中做到。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|892418|crontab+-l+%7C+{+cat;+echo+"0+0+0+0+0+some+entry";+}+%7C+crontab+-|code-block|syntax|javascript|892419|crontab+-l列出当前的crontab作业，cat打印它，echo打印新命令，crontab+-将所有打印的内容添加到crontab文件中。您可以通过执行一个新的crontab+-l来看到效果。|offset|length|style|CODE|892420|entityMap^0|0|0|0|A|P|3|W|4|16|9|2C|A|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|Q|8|@$I|R|J|S|K|L]|$I|T|J|U|K|L]|$I|V|J|W|K|L]|$I|X|J|Y|K|L]|$I|Z|J|10|K|L]]|9|@]|A|$]]|$1|M|3|-4|5|6|7|11|8|@]|9|@]|A|$]]]|N|$]]

You may be able to do it on-the-fly

<pre><code>crontab -l | { cat; echo "0 0 0 0 0 some entry"; } | crontab -
</code></pre>

<code>crontab -l</code> lists the current crontab jobs, <code>cat</code> prints it, <code>echo</code> prints the new command and <code>crontab -</code> adds all the printed stuff into the crontab file. You can see the effect by doing a new <code>crontab -l</code>.

blocks|key|2246250|text|如果您正在使用Vixie，例如，在大多数Linux发行版上，您只需将一个文件放在/etc/cron.d中就可以了。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2246251|当然，这只适用于根。如果您的系统支持这一点，您应该可以在其中看到几个示例。(请注意行中包含的用户名，与旧的/etc/crontab语法相同)|2246252|这是cron中一个令人遗憾的错误，因为它无法作为常规用户来处理，而且如此多的cron实现根本无法处理这个问题。|2246253|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|H|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|I|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|J|8|@]|9|@]|A|$]]|$1|F|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|G|$]]

If you're using the Vixie Cron, e.g. on most Linux distributions, you can just put a file in /etc/cron.d with the individual cronjob.

This only works for root of course. If your system supports this you should see several examples in there. (Note the username included in the line, in the same syntax as the old /etc/crontab)

It's a sad misfeature in cron that there is no way to handle this as a regular user, and that so many cron implementations have no way at all to handle this.

blocks|key|892442|text|很有可能你是在自动化这一点，而且你不希望一个工作增加两次。在这种情况下，使用：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|892443|__cron="1+2+3+4+5+/root/bin/backup.sh"
cat+<(crontab+-l)+%7Cgrep+-v+"${__cron}"+<(echo+"${__cron}")|code-block|syntax|javascript|892444|这只有在你使用BASH的时候才能起作用。我不知道正确的破折号(sh)语法。|offset|length|style|CODE|892445|更新:如果用户还没有crontab，就不能工作。一个更可靠的办法是：|BOLD|892446|(crontab+-l+;+echo+"1+2+3+4+5+/root/bin/backup.sh")+%7C+sort+-+%7C+uniq+-+%7C+crontab+-+|892447|或者，如果发行版支持它，也可以使用一个单独的文件：|892448|echo+"1+2+3+4+5+/root/bin/backup.sh"+%7Csudo+tee+/etc/crond.d/backup|892449|在另一个这样的问题里找到的。|892450|entityMap|0|LINK|mutability|MUTABLE|url|https://stackoverflow.com/questions/610839/how-can-i-programmatically-create-a-new-cron-job^0|0|0|V|2|0|0|I|0|0|0|0|1|8|0|0^^$0|@$1|2|3|4|5|6|7|15|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|16|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|17|8|@$I|18|J|19|K|L]]|9|@]|A|$]]|$1|M|3|N|5|6|7|1A|8|@$I|1B|J|1C|K|O]]|9|@]|A|$]]|$1|P|3|Q|5|D|7|1D|8|@]|9|@]|A|$E|F]]|$1|R|3|S|5|6|7|1E|8|@]|9|@]|A|$]]|$1|T|3|U|5|D|7|1F|8|@]|9|@]|A|$E|F]]|$1|V|3|W|5|6|7|1G|8|@]|9|@$I|1H|J|1I|1|1J]]|A|$]]|$1|X|3|-4|5|6|7|1K|8|@]|9|@]|A|$]]]|Y|$Z|$5|10|11|12|A|$13|14]]]]

Chances are you are automating this, and you don't want a single job added twice.
In that case use:

<pre><code>__cron="1 2 3 4 5 /root/bin/backup.sh"
cat &lt;(crontab -l) |grep -v "${__cron}" &lt;(echo "${__cron}")
</code></pre>

This only works if you're using BASH. I'm not aware of the correct DASH (<code>sh</code>) syntax.

Update: This doesn't work if the user doesn't have a crontab yet. A more reliable way would be: 

<pre><code>(crontab -l ; echo "1 2 3 4 5 /root/bin/backup.sh") | sort - | uniq - | crontab - 
</code></pre>

Alternatively, if your distro supports it, you could also use a separate file: 

<pre><code>echo "1 2 3 4 5 /root/bin/backup.sh" |sudo tee /etc/crond.d/backup
</code></pre>

Found those in <a href="https://stackoverflow.com/questions/610839/how-can-i-programmatically-create-a-new-cron-job">another SO question</a>.

blocks|key|2246325|text|谢谢大家的帮助。把我在这里和其他地方发现的东西拼凑在一起，我想出了如下结论：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2246326|“守则”|2246327|command="php+$INSTALL/indefero/scripts/gitcron.php"
job="0+0+*+*+0+$command"
cat+<(fgrep+-i+-v+"$command"+<(crontab+-l))+<(echo+"$job")+%7C+crontab+-|code-block|syntax|javascript|2246328|我想不出如何在不重复自己的情况下消除这两个变量的需求。|2246329|显然，command是我想要调度的命令。job获取$command并添加调度数据。我在代码行中分别需要这两个变量来完成工作。|offset|length|style|CODE|2246330|详细信息|2246331|恕我直言，我使用这个小重定向工具(<(*command*))将crontab+-l的输出转换为fgrep命令的输入。|ordered-list-item|2246332|然后fgrep过滤掉$command+(-v选项)、不区分大小写(-i选项)的任何匹配项.|2246333|同样，使用小重定向thingy+(<(*command*))将结果转换为cat命令的输入。|2246334|cat命令还通过使用重定向内容(<(*command*))接收echo+"$job"+(不言自明)。|2246335|因此，crontab+-l和简单echo+"$job"的过滤输出结合在一起，将(‘AC.26’)管道传输到crontab+-，以便最终被写入。|2246336|从此以后，他们都过着幸福的生活！|2246337|简而言之：|2246338|这一行代码过滤掉任何与命令匹配的cron作业，然后用新的cron作业写出剩余的cron作业，实际上就像一个“添加”或“更新”函数。要使用它，您所要做的就是交换command和job变量的值。|2246339|entityMap^0|0|0|0|0|3|7|K|3|P|8|0|0|H|C|V|A|1B|5|0|2|5|A|8|K|2|X|2|0|H|C|10|3|0|0|3|G|C|V|B|0|3|A|G|B|1H|9|0|0|0|27|7|2F|3|0^^$0|@$1|2|3|4|5|6|7|1B|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|1C|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|1D|8|@]|9|@]|A|$G|H]]|$1|I|3|J|5|6|7|1E|8|@]|9|@]|A|$]]|$1|K|3|L|5|6|7|1F|8|@$M|1G|N|1H|O|P]|$M|1I|N|1J|O|P]|$M|1K|N|1L|O|P]]|9|@]|A|$]]|$1|Q|3|R|5|6|7|1M|8|@]|9|@]|A|$]]|$1|S|3|T|5|U|7|1N|8|@$M|1O|N|1P|O|P]|$M|1Q|N|1R|O|P]|$M|1S|N|1T|O|P]]|9|@]|A|$]]|$1|V|3|W|5|U|7|1U|8|@$M|1V|N|1W|O|P]|$M|1X|N|1Y|O|P]|$M|1Z|N|20|O|P]|$M|21|N|22|O|P]]|9|@]|A|$]]|$1|X|3|Y|5|U|7|23|8|@$M|24|N|25|O|P]|$M|26|N|27|O|P]]|9|@]|A|$]]|$1|Z|3|10|5|U|7|28|8|@$M|29|N|2A|O|P]|$M|2B|N|2C|O|P]|$M|2D|N|2E|O|P]]|9|@]|A|$]]|$1|11|3|12|5|U|7|2F|8|@$M|2G|N|2H|O|P]|$M|2I|N|2J|O|P]|$M|2K|N|2L|O|P]]|9|@]|A|$]]|$1|13|3|14|5|U|7|2M|8|@]|9|@]|A|$]]|$1|15|3|16|5|6|7|2N|8|@]|9|@]|A|$]]|$1|17|3|18|5|6|7|2O|8|@$M|2P|N|2Q|O|P]|$M|2R|N|2S|O|P]]|9|@]|A|$]]|$1|19|3|-4|5|6|7|2T|8|@]|9|@]|A|$]]]|1A|$]]

Thanks everybody for your help. Piecing together what I found here and elsewhere I came up with this:

<h2>The Code</h2>

<pre><code>command="php $INSTALL/indefero/scripts/gitcron.php"
job="0 0 * * 0 $command"
cat &lt;(fgrep -i -v "$command" &lt;(crontab -l)) &lt;(echo "$job") | crontab -
</code></pre>

I couldn't figure out how to eliminate the need for the two variables without repeating myself.

<code>command</code> is obviously the command I want to schedule. <code>job</code> takes <code>$command</code> and adds the scheduling data. I needed both variables separately in the line of code that does the work.

<h2>Details</h2>

<ol>
<li>Credit to duckyflip, I use this little redirect thingy (<code>&lt;(*command*)</code>) to turn the output of <code>crontab -l</code> into input for the <code>fgrep</code> command.</li>
<li><code>fgrep</code> then filters out any matches of <code>$command</code> (<code>-v</code> option), case-insensitive (<code>-i</code> option).</li>
<li>Again, the little redirect thingy (<code>&lt;(*command*)</code>) is used to turn the result back into input for the <code>cat</code> command.</li>
<li>The <code>cat</code> command also receives <code>echo "$job"</code> (self explanatory), again, through use of the redirect thingy (<code>&lt;(*command*)</code>).</li>
<li>So the filtered output from <code>crontab -l</code> and the simple <code>echo "$job"</code>, combined, are piped ('|') over to <code>crontab -</code> to finally be written.</li>
<li>And they all lived happily ever after!</li>
</ol>

<h2>In a nutshell:</h2>

This line of code filters out any cron jobs that match the command, then writes out the remaining cron jobs with the new one, effectively acting like an "add" or "update" function.
To use this, all you have to do is swap out the values for the <code>command</code> and <code>job</code> variables.

blocks|key|720464|text|这个较短的文件不需要临时文件，它不受多次插入的影响，它允许您更改现有条目的日程安排。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|720465|说你有这些：|720466|croncmd="/home/me/myfunction+myargs+>+/home/me/myfunction.log+2>&1"
cronjob="0+*/15+*+*+*+$croncmd"|code-block|syntax|javascript|720467|若要将其添加到crontab中，不需要重复：|720468|(+crontab+-l+%7C+grep+-v+-F+"$croncmd"+;+echo+"$cronjob"+)+%7C+crontab+-|720469|要从crontab中删除它，不管它当前的计划是什么：|720470|(+crontab+-l+%7C+grep+-v+-F+"$croncmd"+)+%7C+crontab+-|720471|备注：|720472|grep+-F匹配字符串，因为我们不想将它解释为正则表达式。|unordered-list-item|720473|我们还忽略了时间调度，只查找命令。这样，可以更改计划，而不需要向crontab添加新行的风险。|720474|entityMap^0|0|0|0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|Z|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|10|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|11|8|@]|9|@]|A|$G|H]]|$1|I|3|J|5|6|7|12|8|@]|9|@]|A|$]]|$1|K|3|L|5|F|7|13|8|@]|9|@]|A|$G|H]]|$1|M|3|N|5|6|7|14|8|@]|9|@]|A|$]]|$1|O|3|P|5|F|7|15|8|@]|9|@]|A|$G|H]]|$1|Q|3|R|5|6|7|16|8|@]|9|@]|A|$]]|$1|S|3|T|5|U|7|17|8|@]|9|@]|A|$]]|$1|V|3|W|5|U|7|18|8|@]|9|@]|A|$]]|$1|X|3|-4|5|6|7|19|8|@]|9|@]|A|$]]]|Y|$]]

This shorter one requires no temporary file, it is immune to multiple insertions, and it lets you change the schedule of an existing entry.

Say you have these:

<pre><code>croncmd="/home/me/myfunction myargs &gt; /home/me/myfunction.log 2&gt;&amp;1"
cronjob="0 */15 * * * $croncmd"
</code></pre>

To add it to the crontab, with no duplication:

<pre><code>( crontab -l | grep -v -F "$croncmd" ; echo "$cronjob" ) | crontab -
</code></pre>

To remove it from the crontab whatever its current schedule:

<pre><code>( crontab -l | grep -v -F "$croncmd" ) | crontab -
</code></pre>

Notes:

<ul>
<li>grep -F matches the string literally, as we do not want to interpret it as a regular expression</li>
<li>We also ignore the time scheduling and only look for the command. This way; the schedule can be changed without the risk of adding a new line to the crontab</li>
</ul>

blocks|key|2246394|text|为了使用BASH脚本创建/替换crontab，我使用了以下表示法：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2246395|crontab+<<EOF
00+09+*+*+1-5+echo+hello
EOF|code-block|syntax|javascript|2246396|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|$]]

For a nice quick and dirty creation/replacement of a crontab from with a BASH script, I used this notation:

<pre><code>crontab &lt;&lt;EOF
00 09 * * 1-5 echo hello
EOF
</code></pre>

blocks|key|720514|text|一个变体，它只在没有找到所需字符串的情况下编辑crontab：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|720515|CMD="/sbin/modprobe+fcpci"
JOB="@reboot+$CMD"
TMPC="mycron"
grep+"$CMD"+-q+<(crontab+-l)+%7C%7C+(crontab+-l>"$TMPC";+echo+"$JOB">>"$TMPC";+crontab+"$TMPC")|code-block|syntax|javascript|720516|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|$]]

A variant which only edits crontab if the desired string is not found there:

<pre><code>CMD="/sbin/modprobe fcpci"
JOB="@reboot $CMD"
TMPC="mycron"
grep "$CMD" -q &lt;(crontab -l) || (crontab -l&gt;"$TMPC"; echo "$JOB"&gt;&gt;"$TMPC"; crontab "$TMPC")
</code></pre>

blocks|key|720561|text|关于crontab的使用，有很多很好的答案，但是没有提到更简单的方法，比如使用cron。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|720562|使用cron将利用位于/etc/crontab、/etc/cron.daily,weekly,hourly或/etc/cron.d/的系统文件和目录。|720563|cat+>+/etc/cron.d/<job>+<<+EOF
SHELL=/bin/bash+
PATH=/sbin:/bin:/usr/sbin:/usr/bin+
MAILTO=root+HOME=/++
01+*+*+*+*+<user>+<command>
EOF|code-block|syntax|javascript|720564|在上面的示例中，我们在/etc/cron.d/中创建了一个文件，为命令的成功执行提供了环境变量，并提供了命令的user和command本身。该文件不应该是可执行的，并且名称应该只包含alpha-数字和连字符(下面是更多的细节)。|720565|为了给出一个彻底的答案，让我们看看crontab和cron/crond之间的区别|720566|crontab+--+maintain+tables+for+driving+cron+for+individual+users|720567|对于那些想在系统上的用户上下文中运行作业的人来说，使用crontab可能是非常有意义的。|720568|cron+--+daemon+to+execute+scheduled+commands|720569|对于那些使用配置管理或希望为其他用户管理作业的用户，在这种情况下，我们应该使用cron。|720570|手册的快速摘录给您提供了一些要做和不做的示例：|720571|/etc/crontab和/etc/cron.d中的文件必须是根用户所有，不能是组或其他可写的。与假脱机区域不同，/etc/cron.d下的文件或/etc/cron.hourly、/etc/cron.day、/etc/cron.Week和/etc/cron.月刊下的文件也可能是符号链接，只要符号链接及其指向的文件都属于root。/etc/cron.d下的文件不需要是可执行的，而/etc/cron.hourly、/etc/cron.day、/etc/cron.Week和/etc/cron.Monetdo下的文件则不需要可执行，因为它们是由run-parts(8)运行的。
资料来源：+http://manpages.ubuntu.com/manpages/trusty/man8/cron.8.html|blockquote|BOLD|720572|从系统的角度来看，以这种方式管理crons更容易、更可伸缩，但并不总是最好的解决方案。|720573|entityMap|0|LINK|mutability|MUTABLE|url|http://manpages.ubuntu.com/manpages/trusty/man8/cron.8.html^0|13|4|0|2|4|B|C|O|T|1I|C|0|0|B|C|1J|4|1O|7|0|H|7|P|A|0|0|R|7|0|0|13|4|0|0|80|5|86|1N|0|0|0^^$0|@$1|2|3|4|5|6|7|1E|8|@$9|1F|A|1G|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|1H|8|@$9|1I|A|1J|B|C]|$9|1K|A|1L|B|C]|$9|1M|A|1N|B|C]|$9|1O|A|1P|B|C]]|D|@]|E|$]]|$1|H|3|I|5|J|7|1Q|8|@]|D|@]|E|$K|L]]|$1|M|3|N|5|6|7|1R|8|@$9|1S|A|1T|B|C]|$9|1U|A|1V|B|C]|$9|1W|A|1X|B|C]]|D|@]|E|$]]|$1|O|3|P|5|6|7|1Y|8|@$9|1Z|A|20|B|C]|$9|21|A|22|B|C]]|D|@]|E|$]]|$1|Q|3|R|5|J|7|23|8|@]|D|@]|E|$K|L]]|$1|S|3|T|5|6|7|24|8|@$9|25|A|26|B|C]]|D|@]|E|$]]|$1|U|3|V|5|J|7|27|8|@]|D|@]|E|$K|L]]|$1|W|3|X|5|6|7|28|8|@$9|29|A|2A|B|C]]|D|@]|E|$]]|$1|Y|3|Z|5|6|7|2B|8|@]|D|@]|E|$]]|$1|10|3|11|5|12|7|2C|8|@$9|2D|A|2E|B|13]]|D|@$9|2F|A|2G|1|2H]]|E|$]]|$1|14|3|15|5|6|7|2I|8|@]|D|@]|E|$]]|$1|16|3|-4|5|6|7|2J|8|@]|D|@]|E|$]]]|17|$18|$5|19|1A|1B|E|$1C|1D]]]]

There have been a lot of good answers around the use of crontab, but no mention of a simpler method, such as using <code>cron</code>.

Using <code>cron</code> would take advantage of system files and directories located at <code>/etc/crontab</code>, <code>/etc/cron.daily,weekly,hourly</code> or <code>/etc/cron.d/</code>:

<pre><code>cat &gt; /etc/cron.d/&lt;job&gt; &lt;&lt; EOF
SHELL=/bin/bash 
PATH=/sbin:/bin:/usr/sbin:/usr/bin 
MAILTO=root HOME=/ 
01 * * * * &lt;user&gt; &lt;command&gt;
EOF
</code></pre>

In this above example, we created a file in <code>/etc/cron.d/</code>, provided the environment variables for the command to execute successfully, and provided the <code>user</code> for the command, and the <code>command</code> itself. This file should not be executable and the name should only contain alpha-numeric and hyphens (more details below).

To give a thorough answer though, let's look at the differences between <code>crontab</code> vs <code>cron/crond</code>:

<pre><code>crontab -- maintain tables for driving cron for individual users
</code></pre>

For those who want to run the job in the context of their user on the system, using <code>crontab</code> may make perfect sense.

<pre><code>cron -- daemon to execute scheduled commands
</code></pre>

For those who use configuration management or want to manage jobs for other users, in which case we should use <code>cron</code>.

A quick excerpt from the manpages gives you a few examples of what to and not to do:

<blockquote>
 /etc/crontab and the files in /etc/cron.d must be owned by root, and must not be group- or other-writable. In contrast to the spool area, the files under /etc/cron.d or the files under /etc/cron.hourly, /etc/cron.daily, /etc/cron.weekly and /etc/cron.monthly may also be symlinks, provided that both the symlink and the file it points to are owned by root. The files under /etc/cron.d do not need to be executable, while the files under /etc/cron.hourly, /etc/cron.daily, /etc/cron.weekly and /etc/cron.monthly do, as they are run by run-parts (see run-parts(8) for more information).
 
 Source: <a href="http://manpages.ubuntu.com/manpages/trusty/man8/cron.8.html" rel="noreferrer">http://manpages.ubuntu.com/manpages/trusty/man8/cron.8.html</a>
</blockquote>

Managing crons in this manner is easier and more scalable from a system perspective, but will not always be the best solution.

blocks|key|720591|text|下面是一个bash函数，用于在没有重复的情况下向crontab添加命令|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|720592|function+addtocrontab+()+{
++local+frequency=$1
++local+command=$2
++local+job="$frequency+$command"
++cat+<(fgrep+-i+-v+"$command"+<(crontab+-l))+<(echo+"$job")+%7C+crontab+-
}
addtocrontab+"0+0+1+*+*"+"echo+hello"|code-block|syntax|javascript|720593|entityMap^0|O|7|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@$9|N|A|O|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|P|8|@]|D|@]|E|$I|J]]|$1|K|3|-4|5|6|7|Q|8|@]|D|@]|E|$]]]|L|$]]

Here is a bash function for adding a command to <code>crontab</code> without duplication

<pre><code>function addtocrontab () {
 local frequency=$1
 local command=$2
 local job="$frequency $command"
 cat &lt;(fgrep -i -v "$command" &lt;(crontab -l)) &lt;(echo "$job") | crontab -
}
addtocrontab "0 0 1 * *" "echo hello"
</code></pre>

blocks|key|720622|text|脚本函数来添加cron作业。检查重复条目，可用表达式*>“|type|unstyled|depth|inlineStyleRanges|entityRanges|data|720623|cronjob_creator+()+{+++++++++
#+usage:+cronjob_creator+'<interval>'+'<command>'

++if+[[+-z+$1+]]+;then
++++printf+"+no+interval+specified\n"
elif+[[+-z+$2+]]+;then
++++printf+"+no+command+specified\n"
else
++++CRONIN="/tmp/cti_tmp"
++++crontab+-l+%7C+grep+-vw+"$1+$2"+>+"$CRONIN"
++++echo+"$1+$2"+>>+$CRONIN
++++crontab+"$CRONIN"
++++rm+$CRONIN
fi
}|code-block|syntax|javascript|720624|经测试：|720625|$+./cronjob_creator.sh+'*/10+*+*+*+*'+'echo+"this+is+a+test"+>+export_file'
$+crontab++-l
$+*/10+*+*+*+*+echo+"this+is+a+test"+>+export_file|720626|资料来源:我的大脑;)|720627|entityMap^0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|Q|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|R|8|@]|9|@]|A|$E|F]]|$1|K|3|L|5|6|7|S|8|@]|9|@]|A|$]]|$1|M|3|-4|5|6|7|T|8|@]|9|@]|A|$]]]|N|$]]

script function to add cronjobs. check duplicate entries,useable expressions * > "

<pre><code>cronjob_creator () { 
# usage: cronjob_creator '&lt;interval&gt;' '&lt;command&gt;'

 if [[ -z $1 ]] ;then
 printf " no interval specified\n"
elif [[ -z $2 ]] ;then
 printf " no command specified\n"
else
 CRONIN="/tmp/cti_tmp"
 crontab -l | grep -vw "$1 $2" &gt; "$CRONIN"
 echo "$1 $2" &gt;&gt; $CRONIN
 crontab "$CRONIN"
 rm $CRONIN
fi
}
</code></pre>

tested :

<pre><code>$ ./cronjob_creator.sh '*/10 * * * *' 'echo "this is a test" &gt; export_file'
$ crontab -l
$ */10 * * * * echo "this is a test" &gt; export_file
</code></pre>

source : my brain ;)

blocks|key|720637|text|CRON="1+2+3+4+5+/root/bin/backup.sh"+
cat+<+(crontab+-l)+%7Cgrep+-v+"${CRON}"+<+(echo+"${CRON}")|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|720638|将-w参数添加到grep精确命令中，而不使用-w参数添加cron作业"testing“导致删除cron作业"testing123”。|unstyled|720639|脚本函数来添加/删除cron作业。无重复条目：|720640|cronjob_editor+()+{+++++++++
#+usage:+cronjob_editor+'<interval>'+'<command>'+<add%7Cremove>

if+[[+-z+"$1"+]]+;then+printf+"+no+interval+specified\n"+;fi
if+[[+-z+"$2"+]]+;then+printf+"+no+command+specified\n"+;fi
if+[[+-z+"$3"+]]+;then+printf+"+no+action+specified\n"+;fi

if+[[+"$3"+==+add+]]+;then
++++#+add+cronjob,+no+duplication:
++++(+crontab+-l+%7C+grep+-v+-F+-w+"$2"+;+echo+"$1+$2"+)+%7C+crontab+-
elif+[[+"$3"+==+remove+]]+;then
++++#+remove+cronjob:
++++(+crontab+-l+%7C+grep+-v+-F+-w+"$2"+)+%7C+crontab+-
fi+
}+
cronjob_editor+"$1"+"$2"+"$3"|720641|经测试：|720642|$+./cronjob_editor.sh+'*/10+*+*+*+*'+'echo+"this+is+a+test"+>+export_file'+add
$+crontab++-l
$+*/10+*+*+*+*+echo+"this+is+a+test"+>+export_file|720643|entityMap^0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@]|A|$B|C]]|$1|D|3|E|5|F|7|R|8|@]|9|@]|A|$]]|$1|G|3|H|5|F|7|S|8|@]|9|@]|A|$]]|$1|I|3|J|5|6|7|T|8|@]|9|@]|A|$B|C]]|$1|K|3|L|5|F|7|U|8|@]|9|@]|A|$]]|$1|M|3|N|5|6|7|V|8|@]|9|@]|A|$B|C]]|$1|O|3|-4|5|F|7|W|8|@]|9|@]|A|$]]]|P|$]]

<pre><code>CRON="1 2 3 4 5 /root/bin/backup.sh" 
cat &lt; (crontab -l) |grep -v "${CRON}" &lt; (echo "${CRON}")
</code></pre>

add -w parameter to grep exact command, without -w parameter adding the cronjob "testing" cause deletion of cron job "testing123"

script function to add/remove cronjobs. no duplication entries :

<pre><code>cronjob_editor () { 
# usage: cronjob_editor '&lt;interval&gt;' '&lt;command&gt;' &lt;add|remove&gt;

if [[ -z "$1" ]] ;then printf " no interval specified\n" ;fi
if [[ -z "$2" ]] ;then printf " no command specified\n" ;fi
if [[ -z "$3" ]] ;then printf " no action specified\n" ;fi

if [[ "$3" == add ]] ;then
 # add cronjob, no duplication:
 ( crontab -l | grep -v -F -w "$2" ; echo "$1 $2" ) | crontab -
elif [[ "$3" == remove ]] ;then
 # remove cronjob:
 ( crontab -l | grep -v -F -w "$2" ) | crontab -
fi 
} 
cronjob_editor "$1" "$2" "$3"
</code></pre>

tested :

<pre><code>$ ./cronjob_editor.sh '*/10 * * * *' 'echo "this is a test" &gt; export_file' add
$ crontab -l
$ */10 * * * * echo "this is a test" &gt; export_file
</code></pre>

blocks|key|892567|text|我更喜欢的解决办法是：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|892568|(crontab+-l+%7C+grep+.+;+echo+-e+"0+4+*+*+*+myscript\n")+%7C+crontab+-|code-block|syntax|javascript|892569|这将确保您正在正确地处理底部的空白新行。为了避免crontab出现问题，通常应该在crontab文件末尾加上一个空白的新行。上面的脚本确保它首先删除带有"grep“的任何空行。部分，然后在脚本末尾添加一个新的空行，并添加"\n“。如果现有的crontab文件以空行结尾，这还将防止在新命令的上方获得空行。|892570|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

My preferred solution to this would be this:

<pre><code>(crontab -l | grep . ; echo -e "0 4 * * * myscript\n") | crontab -
</code></pre>

This will make sure you are handling the blank new line at the bottom correctly. To avoid issues with crontab you should usually end the crontab file with a blank new line. And the script above makes sure it first removes any blank lines with the "grep ." part, and then add in a new blank line at the end with the "\n" in the end of the script. This will also prevent getting a blank line above your new command if your existing crontab file ends with a blank line.

blocks|key|892599|text|所以，在Debian，Ubuntu和许多类似的基于Debian的发行版中.|type|unstyled|depth|inlineStyleRanges|entityRanges|data|892600|有一个cron任务连接机制，它接受一个配置文件，将它们打包并添加到运行中的cron服务中。|892601|您可以将一个文件放在/etc/cron.d/somefilename下面，在该文件中，somefilename是您想要的。|892602|sudo+echo+"0,15,30,45+*+*+*+*+ntpdate+-u+time.nist.gov"+>>+/etc/cron.d/vmclocksync|code-block|syntax|javascript|892603|让我们拆开这个：|892604|sudo+-因为您需要提升权限才能更改cron目录下的cron信任。|892605|echo+-一种用于在std+out上创建输出的工具。小猫..。也会起作用|892606|“--在你的字符串开头用双引号，你是专业的|892607|0,+15+,30,45+***-标准的cron运行计划，这个每15分钟运行一次。|892608|ntpdate+-u+time.nist.gov+-我想运行的实际命令|892609|“-因为我的第一个双引号需要一个伙伴来关闭正在输出的行|892610|blockquote|892611|双重定向追加而不是覆盖*|unordered-list-item|892612|892613|/etc/cron.d/vmclocksync+-+vmclocksync是我选择的文件名，它位于/etc/cron.d/|892614|*如果我们使用>重定向，我们可以保证我们只有一个任务条目。但是，我们将面临着将现有文件中的任何其他规则吹走的风险。您可以自己决定，如果可能的话，销毁与>是正确的，或可能的重复与>>是为您。或者，你可以做一些复杂的或涉及到的事情来检查文件名是否存在，其中是否有任何内容，以及你是否在添加任何重复--但是，我有事情要做，我现在不能为你做。|892615|entityMap^0|0|0|0|0|0|0|0|0|0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|1A|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|1B|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|1C|8|@]|9|@]|A|$]]|$1|F|3|G|5|H|7|1D|8|@]|9|@]|A|$I|J]]|$1|K|3|L|5|6|7|1E|8|@]|9|@]|A|$]]|$1|M|3|N|5|6|7|1F|8|@]|9|@]|A|$]]|$1|O|3|P|5|6|7|1G|8|@]|9|@]|A|$]]|$1|Q|3|R|5|6|7|1H|8|@]|9|@]|A|$]]|$1|S|3|T|5|6|7|1I|8|@]|9|@]|A|$]]|$1|U|3|V|5|6|7|1J|8|@]|9|@]|A|$]]|$1|W|3|X|5|6|7|1K|8|@]|9|@]|A|$]]|$1|Y|3|-4|5|Z|7|1L|8|@]|9|@]|A|$]]|$1|10|3|11|5|12|7|1M|8|@]|9|@]|A|$]]|$1|13|3|-4|5|6|7|1N|8|@]|9|@]|A|$]]|$1|14|3|15|5|6|7|1O|8|@]|9|@]|A|$]]|$1|16|3|17|5|6|7|1P|8|@]|9|@]|A|$]]|$1|18|3|-4|5|6|7|1Q|8|@]|9|@]|A|$]]]|19|$]]

So, in Debian, Ubuntu, and many similar Debian based distros...

There is a cron task concatenation mechanism that takes a config file, bundles them up and adds them to your cron service running.

You can put a file under the /etc/cron.d/somefilename where somefilename is whatever you want.

<pre><code>sudo echo "0,15,30,45 * * * * ntpdate -u time.nist.gov" &gt;&gt; /etc/cron.d/vmclocksync
</code></pre>

Let's disassemble this:

sudo - because you need elevated privileges to change cron configs under the /etc directory

echo - a vehicle to create output on std out. printf, cat... would work as well

" - use a doublequote at the beginning of your string, you're a professional

0,15,30,45 * * * * - the standard cron run schedule, this one runs every 15 minutes

ntpdate -u time.nist.gov - the actual command I want to run

" - because my first double quotes needs a buddy to close the line being output

>> - the double redirect appends instead of overwrites*

/etc/cron.d/vmclocksync - vmclocksync is the filename I've chosen, it goes in /etc/cron.d/

<hr>

* if we used the > redirect, we could guarantee we only had one task entry. But, we would be at risk of blowing away any other rules in an existing file. You can decide for yourself if possible destruction with > is right or possible duplicates with >> are for you. Alternatively, you could do something convoluted or involved to check if the file name exists, if there is anything in it, and whether you are adding any kind of duplicate-- but, I have stuff to do and I can't do that for you right now.

blocks|key|892623|text|在没有交互式编辑器的情况下添加cron作业的Bash脚本。下面的代码有助于使用linux文件添加cron作业。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|892624|#!/bin/bash

cron_path=/var/spool/cron/crontabs/root

#cron+job+to+run+every+10+min.
echo+"*/10+*+*+*+*+command+to+be+executed"+>>+$cron_path

#cron+job+to+run+every+1+hour.
echo+"0+*/1+*+*+*+command+to+be+executed"+>>+$cron_path|code-block|syntax|javascript|892625|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|$]]

Bash script for adding cron job without the interactive editor.
Below code helps to add a cronjob using linux files.

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

cron_path=/var/spool/cron/crontabs/root

#cron job to run every 10 min.
echo "*/10 * * * * command to be executed" &gt;&gt; $cron_path

#cron job to run every 1 hour.
echo "0 */1 * * * command to be executed" &gt;&gt; $cron_path
</code></pre>

blocks|key|2246642|text|echo+"0+*+*+*+*+docker+system+prune+--force+>/dev/null+2>&1"+%7C+sudo+tee+/etc/cron.daily/dockerprune|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|2246643|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

<pre><code>echo "0 * * * * docker system prune --force &gt;/dev/null 2&gt;&amp;1" | sudo tee /etc/cron.daily/dockerprune
</code></pre>

blocks|key|892627|text|​|type|ordered-list-item|depth|inlineStyleRanges|entityRanges|data|892628|(2>/dev/null+crontab+-l+;+echo+"0+3+*+*+*+/usr/local/bin/certbot-auto+renew")+%7C+crontab+-|code-block|syntax|javascript|892629|892630|cat+<(crontab+-l+2>/dev/null)+<(echo+"0+3+*+*+*+/usr/local/bin/certbot-auto+renew")+%7C+crontab+-|892631|892632|#写出当前的crontab|unstyled|892633|crontab+-l+>+mycron+2>/dev/null|892634|#将新的cron回显为cron文件|892635|echo+"0+3+*+*+*+/usr/local/bin/certbot-auto+renew"+>>+mycron|892636|#安装新的cron文件|892637|crontab+mycron

rm+mycron|892638|entityMap^0|0|0|0|0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|Z|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|10|8|@]|9|@]|A|$E|F]]|$1|G|3|4|5|6|7|11|8|@]|9|@]|A|$]]|$1|H|3|I|5|D|7|12|8|@]|9|@]|A|$E|F]]|$1|J|3|4|5|6|7|13|8|@]|9|@]|A|$]]|$1|K|3|L|5|M|7|14|8|@]|9|@]|A|$]]|$1|N|3|O|5|D|7|15|8|@]|9|@]|A|$E|F]]|$1|P|3|Q|5|M|7|16|8|@]|9|@]|A|$]]|$1|R|3|S|5|D|7|17|8|@]|9|@]|A|$E|F]]|$1|T|3|U|5|M|7|18|8|@]|9|@]|A|$]]|$1|V|3|W|5|D|7|19|8|@]|9|@]|A|$E|F]]|$1|X|3|-4|5|M|7|1A|8|@]|9|@]|A|$]]]|Y|$]]

<ol>
<li></li>
</ol>
<pre><code>(2&gt;/dev/null crontab -l ; echo &quot;0 3 * * * /usr/local/bin/certbot-auto renew&quot;) | crontab -
</code></pre>
<ol start="2">
<li></li>
</ol>
<pre><code>cat &lt;(crontab -l 2&gt;/dev/null) &lt;(echo &quot;0 3 * * * /usr/local/bin/certbot-auto renew&quot;) | crontab -
</code></pre>
<ol start="3">
<li></li>
</ol>
#write out current crontab
<pre><code>crontab -l &gt; mycron 2&gt;/dev/null
</code></pre>
#echo new cron into cron file
<pre><code>echo &quot;0 3 * * * /usr/local/bin/certbot-auto renew&quot; &gt;&gt; mycron
</code></pre>
#install new cron file
<pre><code>crontab mycron

rm mycron
</code></pre>

blocks|key|2246668|text|假设您是以用户"ubuntu“的身份登录的，但是您希望将一个作业添加到另一个用户的crontab中，例如"john”。您可以执行以下操作：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2246669|(sudo+crontab+-l+-u+john;+echo+"*+*+*+*+*+command")+%7C+awk+'!x[$0]%2B%2B'+%7C+sudo+crontab+-u+john+-|code-block|syntax|javascript|2246670|此解决方案的大部分来源：https://www.baeldung.com/linux/create-crontab-script|offset|length|2246671|我在试图将作业添加到(另一个用户的crontab+)时遇到了很多问题。它一直在复制crontab，或者干脆删除它们。不过，经过一些测试后，我确信这一行代码将向指定用户的crontab添加一个新作业，这是非破坏性的，包括不创建一个已经存在的作业。|style|BOLD|2246672|entityMap|0|LINK|mutability|MUTABLE|url|https://www.baeldung.com/linux/create-crontab-script^0|0|0|C|1G|0|0|A|E|26|18|0^^$0|@$1|2|3|4|5|6|7|W|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|X|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|Y|8|@]|9|@$I|Z|J|10|1|11]]|A|$]]|$1|K|3|L|5|6|7|12|8|@$I|13|J|14|M|N]|$I|15|J|16|M|N]]|9|@]|A|$]]|$1|O|3|-4|5|6|7|17|8|@]|9|@]|A|$]]]|P|$Q|$5|R|S|T|A|$U|V]]]]

Say you're logged in as the user &quot;ubuntu&quot;, but you want to add a job to a different user's crontab, like &quot;john&quot;, for example. You can do the following:
<pre><code>(sudo crontab -l -u john; echo &quot;* * * * * command&quot;) | awk '!x[$0]++' | sudo crontab -u john -
</code></pre>
Source for most of this solution: <a href="https://www.baeldung.com/linux/create-crontab-script" rel="nofollow noreferrer">https://www.baeldung.com/linux/create-crontab-script</a>
I was having tons of issues trying to add a job to another user's crontab. It kept duplicating crontabs, or just flat-out deleting them. After some testing, though, I'm confident this line of code will append a new job to a specified user's crontab, non-destructively, including not creating a job that already exists.

blocks|key|2246695|text|我想找个这样的例子，所以也许会有帮助：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2246696|COMMAND="/var/lib/postgresql/backup.sh"
CRON="0+0+*+*+*"
USER="postgres"
CRON_FILE="postgres-backup"
#+At+CRON+times,+the+USER+will+run+the+COMMAND
echo+"$CRON+$USER+$COMMAND"+%7C+sudo+tee+/etc/cron.d/$CRON_FILE
echo+"Cron+job+created.+Remove+/etc/cron.d/$CRON_FILE+to+stop+it."|code-block|syntax|javascript|2246697|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|$]]

I wanted to find an example like this, so maybe it helps:
<pre><code>COMMAND=&quot;/var/lib/postgresql/backup.sh&quot;
CRON=&quot;0 0 * * *&quot;
USER=&quot;postgres&quot;
CRON_FILE=&quot;postgres-backup&quot;
# At CRON times, the USER will run the COMMAND
echo &quot;$CRON $USER $COMMAND&quot; | sudo tee /etc/cron.d/$CRON_FILE
echo &quot;Cron job created. Remove /etc/cron.d/$CRON_FILE to stop it.&quot;
</code></pre>

Does <code>crontab</code> have an argument for creating cron jobs without using the editor (<code>crontab -e</code>)? If so, what would be the code to create a cron job from a Bash script?

How to create a cron job using Bash automatically without the interactive editor?

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。

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crontab是否有理由在不使用编辑器(crontab -e)的情况下创建cron作业？如果是这样的话，从Bash脚本创建cron作业的代码是什么？

问如何在没有交互式编辑器的情况下使用Bash自动创建cron作业？
EN

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问如何在没有交互式编辑器的情况下使用Bash自动创建cron作业？EN