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We recently moved to AWS EC2 instances w/ the Amazon Linux distro.

On our old servers (RH Enterprise), we've been able to run a command in the background (&) and also redirect the output to a log file, such as the below:

php /path/to/script > log.txt &

However, this no longer works on AWS. log.txt is created, but is empty.

If I leave off the & so the task runs in the foreground (php /path/to/script > log.txt), it works and log.txt contains data.

What am I doing wrong here and/or what can I do to get the output of my scripts logged again?

Thanks in advance.

Here's a code sample of what is happening:

[ec2-user@ip /]$ cat logtest.php
<?php echo "It's big, it's heavy, it's wood!\n"; ?>
[ec2-user@ip /]$ php logtest.php > log.txt
[ec2-user@ip /]$ cat log.txt
It's big, it's heavy, it's wood!
[ec2-user@ip /]$ rm log.txt
[ec2-user@ip /]$ php logtest.php > log.txt &
[3] 6649
[ec2-user@ip /]$ <I waited 5 seconds and pressed enter here>
[3]+  Stopped                 php logtest.php > log.txt
[ec2-user@ip /]$ cat log.txt
[ec2-user@ip /]$ ll log.txt
-rw-rw-r-- 1 ec2-user ec2-user 0 Jan  3 00:30 log.txt
[ec2-user@ip /]$
DOOManiac
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5 Answers5

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I'm pretty sure it's related to your /etc/php.ini config or the way the php package is compiled for Amazon Linux. I tried on MacOS and it works fine too. Can you compare the one you have locally to the one you have in AWS.

Try the following on both machines. Create a script called logtest.sh 

#!/bin/bash
echo "It's big, it's heavy, it's wood!\n"

then run:

chmod 777 logtest.sh
./logtest.sh > log.txt &

If it works on both machines then it's definitely a php configuration issue.

Rico
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  • You can also try running `php -i` on both machines and compare the output and see what's different on the configs. – Rico Jan 03 '14 at 01:07
  • This worked as well as Ronald's `echo`, so I guess it's a PHP configuration error. Now to find out what it could be... – DOOManiac Jan 03 '14 at 14:43
  • After more digging, it turns out the culprit is the `readline` extension, which was turned on in the copy of PHP that YUM supplies. Doh! http://php.net/manual/en/book.readline.php#107349 Anyone know how I can disable the extension without recompiling? It isn't in php.ini because it was compiled in... – DOOManiac Jan 03 '14 at 15:23
  • Upvote for the Ren & Stimpy reference – jcbwlkr May 06 '14 at 17:03
0

Try running it with nohup

nohup php /path/to/script > log.txt &
Rico
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  • When I add nohup to my command, it just hangs there instead of automatically sending it to the background like & should do? Even after the process finished I was sitting there waiting on nohup until I hit CTRL+C... – DOOManiac Jan 03 '14 at 00:18
  • What is your php script doing ? – Rico Jan 03 '14 at 00:26
  • It echos "Hi\n" to the screen and quits. I'll update my question with a code sample. – DOOManiac Jan 03 '14 at 00:28
  • If I do `nohup php /path/to/script > log.txt` (no &) and then press CTRL+Z to suspend the job and `bg` to resume it, THAT works... but it's kind of a pain... – DOOManiac Jan 03 '14 at 00:35
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Strange... it works for me, en amazon, but Debian.


root@domU-12-31-39-0F-31-10:/home/try$ php i.php
It's big, it's heavy, it's wood!

root@domU-12-31-39-0F-31-10:/home/try$ php i.php >loh.txt &
[1] 8928
root@domU-12-31-39-0F-31-10:/home/try$
[1]+  Done                    php i.php > loh.txt
root@domU-12-31-39-0F-31-10:/home/try$
root@domU-12-31-39-0F-31-10:/home/try$ cat loh.txt
It's big, it's heavy, it's wood!
3.14
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0

Also you can use screen ?? man screen

3.14
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can you try to do this, in the same directory where your log is ?

echo "test" > log.txt

It'll may disqualifie a file system full and read only file system options.

Ronald Pauffert
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