To check if some system service is active and then activate/deactivate it use the next code:
#!/bin/bash
systemctl -q is-active jackett.service && \
systemctl stop jackett.service || \
systemctl start jackett.service
To check if some system service is active and then activate/deactivate it use the next code:
#!/bin/bash
systemctl -q is-active jackett.service && \
systemctl stop jackett.service || \
systemctl start jackett.service