-- Execute the command as "should be done" and look at the file content. As we run it with nowait, we get a 1 inmediately
zabbix72:~$ time zabbix_get -s zabbix-agent2 -k system.run["echo Hello - \$(date) >> /var/lib/zabbix/prueba.txt",nowait] -t 1;\
echo;\
time zabbix_get -s zabbix-agent2 -k vfs.file.contents[/var/lib/zabbix/prueba.txt]
1

real    0m0.003s
user    0m0.002s
sys     0m0.000s


Hello - Wed Jul 23 14:19:11 UTC 2025

real    0m0.002s
user    0m0.001s
sys     0m0.000s

-- As should not be done (without nowait), but it's so fast that we get no error (and no return), but the file is modified
zabbix72:~$ time zabbix_get -s zabbix-agent2 -k system.run["echo Hello - \$(date) >> /var/lib/zabbix/prueba.txt"] -t 1 ;\
echo ;\
time zabbix_get -s zabbix-agent2 -k vfs.file.contents[/var/lib/zabbix/prueba.txt]


real    0m0.008s
user    0m0.001s
sys     0m0.002s


Hello - Wed Jul 23 14:19:11 UTC 2025
Hello - Wed Jul 23 14:19:29 UTC 2025

real    0m0.002s
user    0m0.000s
sys     0m0.001s

-- Execute the command as "should be done" and look at the file content. 
-- As we run it with nowait, we get a 1 inmediately
-- at first the file only have the first line
-- we wait 3 seconds and then the file have th "Bye" line too
zabbix72:~$ time zabbix_get -s zabbix-agent2 -k system.run["echo Hello - \$(date) >> /var/lib/zabbix/prueba.txt; sleep 3; echo Bye - \$(date) >> /var/lib/zabbix/prueba.txt",nowait] -t 1;\
echo;\
time zabbix_get -s zabbix-agent2 -k vfs.file.contents[/var/lib/zabbix/prueba.txt];\
sleep 3;\
time zabbix_get -s zabbix-agent2 -k vfs.file.contents[/var/lib/zabbix/prueba.txt]
1

real    0m0.003s
user    0m0.000s
sys     0m0.002s


Hello - Wed Jul 23 14:19:11 UTC 2025
Hello - Wed Jul 23 14:19:29 UTC 2025
Hello - Wed Jul 23 14:23:43 UTC 2025

real    0m0.003s
user    0m0.002s
sys     0m0.000s

Hello - Wed Jul 23 14:19:11 UTC 2025
Hello - Wed Jul 23 14:19:29 UTC 2025
Hello - Wed Jul 23 14:23:43 UTC 2025
Bye - Wed Jul 23 14:23:46 UTC 2025

real    0m0.002s
user    0m0.002s
sys     0m0.000s

--Execute the command waiting, the wrong way
-- We get a timeout message
-- The file is modified, we got the "Hello" line
-- after waiting 3 seconds, we don´t have the "Bye" line, as the command was cancelled
zabbix72:~$ time zabbix_get -s zabbix-agent2 -k system.run["echo Hello - \$(date) >> /var/lib/zabbix/prueba.txt ; sleep 3 ; echo Bye - \$(date) >> /var/lib/zabbix/prueba.txt"] -t 1;\
echo;\
time zabbix_get -s zabbix-agent2 -k vfs.file.contents[/var/lib/zabbix/prueba.txt];\
sleep 3;\
time zabbix_get -s zabbix-agent2 -k vfs.file.contents[/var/lib/zabbix/prueba.txt]
ZBX_NOTSUPPORTED: Timeout while executing a shell script.

real    0m1.004s
user    0m0.002s
sys     0m0.000s


Hello - Wed Jul 23 14:19:11 UTC 2025
Hello - Wed Jul 23 14:19:29 UTC 2025
Hello - Wed Jul 23 14:23:43 UTC 2025
Bye - Wed Jul 23 14:23:46 UTC 2025
Hello - Wed Jul 23 14:24:48 UTC 2025

real    0m0.003s
user    0m0.000s
sys     0m0.002s

Hello - Wed Jul 23 14:19:11 UTC 2025
Hello - Wed Jul 23 14:19:29 UTC 2025
Hello - Wed Jul 23 14:23:43 UTC 2025
Bye - Wed Jul 23 14:23:46 UTC 2025
Hello - Wed Jul 23 14:24:48 UTC 2025

real    0m0.008s
user    0m0.004s
sys     0m0.004s