Every job that&#39;s run by cron is run in the background automatically, so no need for the `&amp;`

See [this][1] too.


  [1]: https://help.ubuntu.com/community/CronHowto

Is there a way to do this? Say I have a file that&#39;s a list of names that goes like this:

 1. Alfred
 2. Bill
 3. Donald

How could I insert the third name, &quot;Charlie&quot;, at line x (in this case 3), and automatically send all others down one line? I&#39;ve seen other questions like this, but they didn&#39;t get helpful answers. Can it be done, preferably with either a method or a loop?

Insert line at middle of file with Python?

Is it possible to change the default background color of a select list option on hover?

HTML:

    &lt;select id=&quot;select&quot;&gt;
        &lt;option value=&quot;1&quot;&gt;One&lt;/option&gt;
        &lt;option value=&quot;2&quot;&gt;Two&lt;/option&gt;
        &lt;option value=&quot;3&quot;&gt;Three&lt;/option&gt;
    &lt;/select&gt;

I have tried  `option:hover { background-color: red; }`, but it is of no use. Does anybody know how to do this?

Change Select List Option background colour on hover

In a crontab file, should commands be specified with a trailing &quot;&amp;&quot;, or will the command run in the background anyway?

I have:

    */20 * * * * /home/me/monitor/check.sh /home/me/monitor/check.properties  &gt;&gt; /home/me/monitor/check.log 2&gt;&amp;1 &amp;

I&#39;ve seen contradictory answers to this question in various places. Some say no need to put an &quot;&amp;&quot;, others that without the ampersand cron waits for output from the command, even though all output is redirected.

Should linux cron jobs be specified with an &quot;&amp;&quot; to indicate to run in background?

In a crontab file, should commands be specified with a trailing "&#x26;", or will the command run in the background anyway?
I have:
<pre><code class="hljs language-ruby">*/20 * * * * /home/me/monitor/check.sh /home/me/monitor/check.properties >> /home/me/monitor/check.log 2>&#x26;1 &#x26;
</code></pre>
I've seen contradictory answers to this question in various places. Some say no need to put an "&#x26;", others that without the ampersand cron waits for output from the command, even though all output is redirected.

I have the following simple script where I am running a loop and want to maintain a `COUNTER`. I am unable to figure out why the counter is not updating. Is it due to subshell thats getting created? How can I potentially fix this?

    #!/bin/bash

    WFY_PATH=/var/log/nginx
    WFY_FILE=error.log
    COUNTER=0
    grep &#39;GET /log_&#39; $WFY_PATH/$WFY_FILE | grep &#39;upstream timed out&#39; | awk -F &#39;, &#39; &#39;{print $2,$4,$0}&#39; | awk &#39;{print &quot;http://domain.com&quot;$5&quot;&amp;ip=&quot;$2&quot;&amp;date=&quot;$7&quot;&amp;time=&quot;$8&quot;&amp;end=1&quot;}&#39; | awk -F &#39;&amp;end=1&#39; &#39;{print $1&quot;&amp;end=1&quot;}&#39; |
    (
    while read WFY_URL
    do
        echo $WFY_URL #Some more action
        COUNTER=$((COUNTER+1))
    done
    )

    echo $COUNTER # output = 0

Counter increment in Bash loop not working

I have this list of files on a Linux server:

    abc.log.2012-03-14
    abc.log.2012-03-27
    abc.log.2012-03-28
    abc.log.2012-03-29
    abc.log.2012-03-30
    abc.log.2012-04-02
    abc.log.2012-04-04
    abc.log.2012-04-05
    abc.log.2012-04-09
    abc.log.2012-04-10

I&#39;ve been deleting selected log files one by one, using the command `rm -rf` see below:

    rm -rf abc.log.2012-03-14
    rm -rf abc.log.2012-03-27
    rm -rf abc.log.2012-03-28

Is there another way, so that I can delete the selected files at once?


How to delete multiple files at once in Bash on Linux?

I am using `ls -l -t` to get a list of files in a directory ordered by time. 

I would like to limit the search result to the top 2 files in the list.&lt;br/&gt;
Is this possible?&lt;br/&gt;
I&#39;ve tried with grep and I struggled.

first two results from ls command

In *scatter* and *gather* (i.e. `readv` and `writev`), Linux reads into multiple buffers and writes from multiple buffers.

If say, I have a vector of 3 buffers, I can use `readv`, OR I can use a single buffer, which is of combined size of 3 buffers and do `fread`.

Hence, I am confused: For which cases should scatter/gather be used and when should a single large buffer be used?

Linux: When to use scatter/gather IO (readv, writev) vs a large buffer with fread

I&#39;m looking for a way to convert xlsx files to csv files on Linux.

I do not want to use PHP/Perl or anything like that since I&#39;m looking at processing several millions of lines, so I need something quick. I found a program on the Ubuntu repos called xls2csv but it will only convert xls (Office 2003) files (which I&#39;m currently using) but I need support for the newer Excel files.

Any ideas?

Convert xlsx to csv in Linux with command line

I want to get the details of the last run cron job. If the job is interrupted due to some internal problems, I want to re-run the cron job. 

Note: I don&#39;t have superuser privilege.

Details of last ran cron job in Unix-like systems?

I&#39;m newbie in cron commands and I need help.

I have a script on `http://example.com/check/`.

Whats is command for cron to run this URL every 5 minutes?

I tried 

&gt; */5 * * * * /home/test/check.php 

But I want to run URL not relative script address. How to do it?

CRON command to run URL address every 5 minutes

Source Wikipedia:   

&gt; **Question mark** (?) is used instead of &#39;*&#39; for leaving either day-of-month or day-of-week blank.

The above statement is not making much sense to me.

So if I write some cron as **`0 0 0 ? * *`** then does it mean first of every month or it means it will execute daily?

It is a bit confusing as Java crons start with seconds while other crons start with minute.

Significance of question mark in Java cron

How can I run command every six hours every day?

I tried the following, but it did not work:

    /6 * * * * *  mycommand




Running a cron job on Linux every six hours

Currently I have a single server in amazon where I put all my cronjobs.  I want to eliminate this single point of failure, and expose all my tasks as web services.  I&#39;d like to expose the services behind a VPC ELB to a few servers that will run the tasks when called.

Is there some service that Amazon (AWS) offers that can run a reoccurring job (really call a webservice) at scheduled intervals?  I&#39;d really like to be able to keep the cron functionality in terms of time/day specification, but farm out the HA of the driver (thing that calls endpoints at the right time) to AWS.

I like how SQS offers web endpoint(s), but from what I can tell you cant schedule them.  SWF doesn&#39;t seem to be a good fit either.



Content Type	Original Author	Original Content on Stackoverflow
Question	user265330	View Question on Stackoverflow
Solution 1 - Linux	Levon	View Answer on Stackoverflow

Should linux cron jobs be specified with an "&" to indicate to run in background?

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Change Select List Option background colour on hover

Insert line at middle of file with Python?

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