Start nginx from shell script on crontab - shell

Question

I want to check NGINX is running or not every 1 minute.
My shell script is:
#!/bin/sh
ps auxw | grep nginx | grep -v grep > /dev/null
if [ $? != 0 ]
then
echo "NGINX is not running"
/etc/init.d/nginx start
else
echo "NGINX is running"
fi
Script run with sh launch.sh correctly (If NGINX is not running, run NGINX).
The problem is when I want to run the script every 1 minute by crontab, nothing happens. Crontab list is here:
# Edit this file to introduce tasks to be run by cron.
#
# Each task to run has to be defined through a single line
# indicating with different fields when the task will be run
# and what command to run for the task
#
# To define the time you can provide concrete values for
# minute (m), hour (h), day of month (dom), month (mon),
# and day of week (dow) or use '*' in these fields (for 'any').#
# Notice that tasks will be started based on the cron's system
# daemon's notion of time and timezones.
#
# Output of the crontab jobs (including errors) is sent through
# email to the user the crontab file belongs to (unless redirected).
#
# For example, you can run a backup of all your user accounts
# at 5 a.m every week with:
# 0 5 * * 1 tar -zcf /var/backups/home.tgz /home/
#
# For more information see the manual pages of crontab(5) and cron(8)
#
# m h dom mon dow command
* * * * * ~/sh launch.sh
I test * * * * * sh launch.sh, * * * * * launch.sh and * * * * * ./launch.sh but none of them work correctly.
My OS is UBUNTU 18.04.
This is log:
Jun 3 08:28:01 hajitsu-VirtualBox CRON[3239]: (root) CMD (~/launch.sh)
Jun 3 08:28:01 hajitsu-VirtualBox CRON[3240]: (hajitsu) CMD (/home/hajitsu/launch.sh)
Jun 3 08:28:01 hajitsu-VirtualBox CRON[3238]: (CRON) info (No MTA installed, discarding output)
Jun 3 08:28:01 hajitsu-VirtualBox CRON[3237]: (CRON) info (No MTA installed, discarding output)
Jun 3 08:29:01 hajitsu-VirtualBox CRON[3374]: (root) CMD (~/launch.sh)
Jun 3 08:29:01 hajitsu-VirtualBox CRON[3373]: (CRON) info (No MTA installed, discarding output)
Jun 3 08:29:01 hajitsu-VirtualBox CRON[3376]: (hajitsu) CMD (/home/hajitsu/launch.sh)
Jun 3 08:29:01 hajitsu-VirtualBox CRON[3372]: (CRON) info (No MTA installed, discarding output)
I think the command fired but nothing happend.

Answer 1

NGINX needs sudo privilege.
If you have sudo privileges you can modify /etc/sudoers.d/username file and execute sudo commands without password.
The file usually contains a user and a list of commands that the user can run without having to specify a password. In your case, you can run:
sudo /etc/init.d/nginx start
Add or modify your sudoers file. (replace username with your username.)
$ EDITOR=nano sudo visudo -f /etc/sudoers.d/username # EDITOR=nano sets my editor (because I am more comfortable with nano)
Copy and paste following.
You can add more sudo commands separating by comma.
username ALL=(ALL) NOPASSWD: /etc/init.d/nginx start,/etc/init.d/nginx start
Note: Commands will only execute called with sudo.
Prepend sudo in your launch.sh:
#!/bin/sh
ps auxw | grep nginx | grep -v grep > /dev/null
if [ $? != 0 ]
then
echo "NGINX is not running"
sudo /etc/init.d/nginx start
else
echo "NGINX is running"
fi
Make file executable.
$ chmod +x launch.sh

Answer 2

~ won't be expanded the way it is in an interactive shell when in a crontab. Use /home/username instead.