Auto-Start Tomcat on Ubuntu Boot Using systemd

Learn how to configure Apache Tomcat to start automatically on system boot in Ubuntu using systemd service units. A complete step-by-step guide.

Apache Tomcat is not configured with autostart by default in Ubuntu. So, custom init script is required to configure Tomcat for autostart on startup.

Create the init script in /etc/init.d/tomcat8 with the contents as per below.

Init script contents:

#!/bin/bash

### BEGIN INIT INFO
# Provides:        tomcat8
# Required-Start:  $network
# Required-Stop:   $network
# Default-Start:   2 3 4 5
# Default-Stop:    0 1 6
# Short-Description: Start/Stop Tomcat server
### END INIT INFO

PATH=/sbin:/bin:/usr/sbin:/usr/bin

start() {
 sh {tomcat_root}/bin/startup.sh
}

stop() {
 sh {tomcat_root}/bin/shutdown.sh
}

case $1 in
  start|stop) $1;;
  restart) stop; start;;
  *) echo "Run as $0 <start|stop|restart>"; exit 1;;
esac

Note: Please change {tomcat_root} with your Tomcat installation folder path.

Change its permissions and add the correct symlinks automatically:

chmod 755 /etc/init.d/tomcat8
update-rc.d tomcat8 defaults

And from now on it will be automatically started and shut down upon entering the appropriate run levels.

It could be also controlled with just use following commands like Apache

service tomcat8 <stop|start|restart>

Using above process any server script can be created and configured to start on startup.

How to Schedule Cron jobs tasks in Unix/Linux

Learn to schedule tasks using cronjob in Unix. This guide explains how to manage cronjob tasks in unix with practical examples.

Cron jobs are essential tools in Unix/Linux systems for automating repetitive tasks. Whether you’re backing up files, syncing data, or running maintenance scripts, cron jobs make sure your tasks run consistently and on time without manual intervention.

In this article, we’ll walk through how to add jobs to the cron scheduler (crontab) and understand its syntax so you can schedule tasks efficiently.

What is a Cron Job in Unix?

A cron job is a scheduled command or script that runs automatically at specified intervals. The cron daemon (crond) handles these jobs in the background on Unix-like operating systems.

Viewing and Editing Crontabation files

Each user has their own crontab file. To view or edit your crontab:

crontab -e

This command opens your crontab in the default system editor (like vi or nano), allowing you to add or modify jobs.

To view your current scheduled jobs:

crontab -l

To remove all scheduled cron jobs:

crontab -r

Unix Cron jobs Syntax Breakdown

A typical cron job line looks like this:

* * * * * command to be executed
- - - - -
| | | | |
| | | | ----- Day of week (0 - 7) (Sunday=0 or 7)
| | | ------- Month (1 - 12)
| | --------- Day of month (1 - 31)
| ----------- Hour (0 - 23)
------------- Minute (0 - 59)

Each * represents a time or date field. And each field can be configured based on the following table.

FieldValue RangeDescription
Minute0–59Minute of the hour
Hour0–23Hour of the day
Day1–31Day of the month
Month1–12Month of the year
Weekday0–7 (0 or 7 = Sunday)Day of the week

Example: Run backup cron job script

If you wished to have a script named /root/backup.sh run every day at 3 am, your crontab entry would look like as follows. First, install your cronjob by running the following command:

# crontab -e

Append the following entry:

0 3 * * * /root/backup.sh

Save and close the file.

More examples

To run /path/to/command five minutes after midnight, every day, enter:

5 0 * * * /path/to/command

Run /path/to/script.sh at 2:15 pm on the first of every month, enter:

15 14 1 * * /path/to/script.sh

To run any PHP script /scripts/phpscript.php at 10 pm on weekdays, enter:

0 22 * * 1-5 /scripts/phpscript.php

Run /root/scripts/perl/perlscript.pl at 23 minutes after midnight, 2am, 4am …, everyday, enter:

23 0-23/2 * * * /root/scripts/perl/perlscript.pl

Run /path/to/unixcommand at 5 after 4 every Sunday, enter:

5 4 * * sun /path/to/unixcommand

You can schedule any command using the cron jobs. For running any script using cron job, make sure your script has executable permissions.

If your script uses environment variables or specific paths, be sure to define them inside the script or call the appropriate environment setup.

Redirecting Output

To log output or errors, you can use the following command and save the logs in file:

0 0 * * * /path/to/script.sh >> /var/log/myscript.log 2>&1
  • >> appends standard output to a log file
  • 2>&1 redirects errors (stderr) to the same log file without displaying it to the console.

System-Wide Cron Jobs

System-wide cron files can be added to:

  • Hourly, daily, weekly, monthly: /etc/cron.hourly/, /etc/cron.daily/, etc.
  • /etc/crontab
  • /etc/cron.d/

Conclusion

Cron jobs are powerful for scheduling recurring tasks in Unix/Linux environments. By mastering crontab syntax and scheduling structure, you can automate system maintenance, backups, and custom scripts with ease.

Make sure to test your scripts before scheduling them and check logs regularly to confirm successful execution.

See also

See man pages for more information cron(8), crontab(1), crontab(5), run-parts(8)

Getting Started with Vi Editor in Unix: Essential Commands & Tips

A beginner-friendly guide to using the Vi editor in Unix. Learn basic navigation, editing, and saving commands to boost your productivity in the terminal.

vi is a command-line text editor originally created for the Unix operating system.

The name vi is derived from the shortest unambiguous abbreviation for the command visual; the command in question switches the line editor ex to visual mode.

Most of the network administrators are familiar with this little editor in Unix, because they use it regularly. But, for first timers, it’s most difficult editor. First timers have to remember all commands and keys to edit a simple file.

vi has two modes, Insert mode and Command mode. In insert mode, you can add/edit the texts in file. And in command mode, you can navigate and command the editor like save, exit, copy, paste, etc.

These are the commands and keys for those who want to get familiar with vi editor.

Command to open the vi editor:

vi filename

This command creates a new file if filename is not available in current directory. By default, vi begins in command mode.

To start the insert mode, you can use following keys:

Insert text at beginning of line:

I

Insert text at cursor:

i

append text after cursor:

a

Append text at line end:

A

Open line above cursor:

O

Open line below cursor:

o

To switching back, and start the Command mode, press [ESC]

Most commands execute as soon as typed except for “colon” commands which execute when you press the return key.

For cursor movement in command mode, you can use following commands/keys:

Go to beginning of line

0

Go to end of line

$

Go to line number ##

:##

Go to line n

nG

Go to last line

G

Left 6 chars

6h

Move left, down, up, right

h j k l

Move left, down, up, right

← ↓ ↑ →

Scroll Backward 1 screen

[ctrl] b

Scroll Forward 1 screen

[ctrl] f

Scroll by sentence forward/backward

( )

Scroll by word forward/backward

w b

Scroll by paragraph forward/backward

{ }

Scroll Up 1/2 screen

[ctrl] u

Scroll Down 1/2 screen

[ctrl] d

For deleting/changing text/character in command mode, you can use following commands/keys:

Change word

cw

Replace one character

r

Delete word

dw

Delete text at cursor

x

Delete entire line (to buffer)

dd

Delete (backspace) text at cursor

X

Delete 5 lines (to buffer)

5dd

Delete current to end of line

D

Delete lines 5-10

:5,10d

For editing content in command mode, you can use following commands/keys:

Copy line

yy

Copy n lines

nyy

Copy lines1-2 /paste after 3

:1,2t3

Move lines 4-5/paste after 6

:4,5m6

Paste above current line

P

Paste below current line

p

Undo all changes to line

U

Undo previous command

u

Join previous line

J

Find next string occurrence

n

Search backward for string

?string

Search forward forstring

/string

% (entire file) s (search and replace) /old text with new/ c (confirm) g (global – all)

:%s/oldstring/newstring/cg

Ignore case during search

:set ic

Repeat last command

.

For saving and quiting in command mode, you can use following commands/keys:

Save changes to buffer

:w

Save changes and quit vi

zz or :wq

Save file to new file

:w file

Quit without saving

:q!

Save lines to new file

:10,15w file

In all of the above commands, a number n will tell vi to repeat that command n times.

:syntax on Turn on syntax highlighting
:syntax off Turn off syntax highlighting
:set number Turn on Line numbering (shorthand :set nu)
:set nonumber Turn off Line numbering (shorthand :set nonu)

:set ignorecase Ignore case sensitivity when searching
:set noignorecase Restore case sensitivity (default)