Can't start a systemd service - service

Question

I am trying to create a service that runs the console to convert all my crontab commands to systemd in the future, but I always get this error, I have tried different tutorials and the same problem.
# systemctl status hello-world.service
● hello-world.service - Hello World Service
Loaded: loaded (/usr/lib/systemd/system/hello-world.service; disabled; vendor preset: disabled)
Active: failed (Result: exit-code) since mié 2019-10-09 10:06:59 CEST; 4s ago
Process: 26080 ExecStart=/usr/share/nginx/html/scripts-systemd/hello-world.sh (code=exited, status=203/EXEC)
Main PID: 26080 (code=exited, status=203/EXEC)
oct 09 10:06:59 ns37 systemd[1]: Started Hello World Service.
oct 09 10:06:59 ns37 systemd[1]: hello-world.service: main process exited, code=exited, status=203/EXEC
oct 09 10:06:59 ns37 systemd[1]: Unit hello-world.service entered failed state.
oct 09 10:06:59 ns37 systemd[1]: hello-world.service failed.
hello-world.sh file
#!/bin/bash
while $(sleep 30);
do
echo "hello world"
done
hello-world.service file
[Unit]
Description=Hello World Service
After=systend-user-sessions.service
[Service]
Type=simple
ExecStart=/usr/share/nginx/html/scripts-systemd/hello-world.sh
[Install]
WantedBy=multi-user.target
Im using Centos 7
Edit:
What I need to do is execute console commands at certain times every day due to problems with crontab.
I was using this example to check that everything works and once it works change the commands.
Here is an example of a crontab command:
*/10 * * * * cd /usr/share/nginx/html/mywebsite.com; php wp-cron.php >/dev/null 2>&1
0 0 */3 * * date=date -I; zip -r /root/copias/copia-archivos-html-webs$date.zip /usr/share/nginx/html`
15 15 * * * wget -q -O /dev/null https://mywebsite.com/?run_plugin=key_0_0
Edit2: Done! I've managed to do it and works for now, I leave the code here so it can be useful for other people
hello-world.sh file
#!/usr/bin/env bash
/usr/bin/mysqldump -user -pass db_name >/root/copias/backupname.sql
hello-world.service
[Unit]
Description=CopiaSql
[Service]
Type=oneshot
ExecStart=/bin/bash /usr/share/nginx/html/scripts-systemd/hello-world.sh
[Install]
WantedBy=multi-user.target
hello-world.timer
[Unit]
Description=Runs every 2 minutes test.sh
[Timer]
OnCalendar=*:0/2
Unit=hello-world.service
[Install]
WantedBy=timers.target
Thanks everyone for your help!

Answer 1

I have a first boot install service that displays on the console and it looks like:
[Unit]
After=multi-user.target
# tty getty service login promts for tty1 & tty6
# will not be seen until this install completes.
Before=getty#tty1.service getty#tty6.service
[Service]
Type=oneshot
ExecStart=/bin/bash -c "export TERM=vt100;/var/ssi/firstboot_install.sh"
StandardOutput=tty
StandardInput=tty
[Install]
WantedBy=multi-user.target
My script that runs also has this code to start
#---------------------------------------------------------------------
# Switch to tty6 so input is allowed from installation questions
# Change back to tty1 at end of this script to show normal booting
# messages from systemd.
#---------------------------------------------------------------------
exec < /dev/tty6 > /dev/tty6
chvt 6
at the end of this script I change it back
# Now that the system has been registered and has a few channels added,
# I can have the installation go back to the main Anaconda output screen
# on tty1
chvt 1
exec < /dev/tty1 > /dev/tty1
exit 0
This might not be exactly what you want but you can adapt it to your needs. The goal here is to display something on the console which starts during the boot sequence. My script which asks a number of installation questions where input is NOT allowed on tty1 (console) which is why I change to tty6 so input is allowed during the first boot installation.
Your script try:
#!/bin/bash
exec < /dev/tty6 > /dev/tty6
chvt 6
while $(sleep 30);
do
echo "hello world"
done
chvt 1
exec < /dev/tty1 > /dev/tty1
This might be overkill for what your trying to do but if you need input
from the console, you should do the same with tty6