Avoid waiting for user when checking the Apache Tomcat status-CodePudding

As part of a bash script I check the recently installed Apache Tomcat status with

sudo systemctl status tomcat

The output is as follows

● tomcat.service
     Loaded: loaded (/etc/systemd/system/tomcat.service; enabled; vendor preset: enabled)
     Active: active (running) since Mon 2023-01-30 16:25:48 UTC; 3min 9s ago
    Process: 175439 ExecStart=/opt/tomcat/bin/startup.sh (code=exited, status=0/SUCCESS)
   Main PID: 175447 (java)
      Tasks: 30 (limit: 4546)
     Memory: 253.0M
        CPU: 9.485s
     CGroup: /system.slice/tomcat.service
             └─175447 /usr/lib/jvm/java-1.11.0-openjdk-amd64/bin/java -Djava.util.logging.config.file=/opt/tomcat/conf/logging.properties -Djava.uti>

Jan 30 16:25:48 vps-06354c04 systemd[1]: Starting tomcat.service...
Jan 30 16:25:48 vps-06354c04 startup.sh[175439]: Tomcat started.
Jan 30 16:25:48 vps-06354c04 systemd[1]: Started tomcat.service.
Jan 30 16:25:48 vps-06354c04 systemd[1]: /etc/systemd/system/tomcat.service:1: Assignment outside of section. Ignoring.
Jan 30 16:25:48 vps-06354c04 systemd[1]: /etc/systemd/system/tomcat.service:2: Assignment outside of section. Ignoring.

This is the info I expect to see, but after printing it, systemctl keeps waiting for the user to type a key, breaking the automation I expect to deliver.

How can I avoid this behaviour?

CodePudding user response：

I'm pretty sure the --no-pager option would keep that from happening. I just confirmed that on my own system on a different service. Otherwise, it goes interactive.

CodePudding user response：

I don't recall ever seeing systemctl status asking for input, so perhaps it's the sudo used in this command doing that, in which case you could ask your system administrator to enable passwordless sudo on the account that runs this command.

A general solution for automating user input in shell scripts is to use expect, but for a simple case where you only need to send a single value one time, you can often get by with using echo and piping the value to the command (e.g., echo 'foo' | sudo systemctl status tomcat), although you should never do this to pass sensitive information such as passwords because that will potentially be accessible to other users on that system.