Scheduling a task to run automatically

Name:

Date:

Class:

Quick Questions

Shade in the A or B circle for each question.

1. What does a scheduler such as cron or Task Scheduler do?

A Runs a command or script at set times without a person starting it

B Runs a script only when a person clicks it

2. Which tool is the built-in task scheduler on Windows?

A Windows Task Scheduler

B cron

3. In a cron expression, what does 30 2 * * * mean?

A Run every 30 minutes for 2 hours

B Run every day at 2:30 am

4. Which cron expression runs a backup at 11:00 pm every day?

A 23 0 * * * /home/backup.sh

B 0 23 * * * /home/backup.sh

5. Why is a scheduler useful for automated backups?

A The backup runs every night even if the user forgets

B The backup is never needed again after the first run

Match the Pairs

Draw a line connecting each item on the left to its match on the right.

Left column		Right column
10 2 * * * python3 backup.py		AA cron entry that runs backup.py automatically at 2:00 am every day
2@reboot /home/user/sync.sh		B30 23 * * 5 /home/user/backup.sh
3Run a backup script automatically at 11:30 pm every Friday using a cron expression		CA cron entry that runs sync.sh each time the computer starts up
4Windows Task Scheduler can create a daily task that starts a backup program from the command line		Dschtasks /create /tn Backup /tr backup.bat /sc daily /st 22:00
52 0 * * * /home/user/backup.sh (meant to run at 2:00 am)		EOnly four time fields are given, so cron reads backup.sh as the fifth time field. A cron entry needs five time fields, such as 0 2 * * * backup.sh.
60 2 * * backup.sh		FThe minute and hour fields are in the wrong order. This runs at 12:02 am, not 2:00 am. It should be 0 2 * * *.

Definitions

cron

Fill in the Blanks

Complete each line of code by filling in the missing parts.

# Run backup.sh at 2am every day 0 _ * * * /home/ava/backup.sh

# Run backup.sh once at start-up @______ /home/ava/backup.sh

# Edit your list of scheduled cron jobs _______ -e

# Windows Task Scheduler: run every day schtasks /create /tn "Backup" /sc _____

# Run backup.sh every day at 6:30pm __ 18 * * * /home/ava/backup.sh

Spot the Error

Shade in the letter of the line that contains an error.

Question 1

A 0 2 * * /home/ann/backup.sh

B 30 6 * * 1 /home/ann/clean.sh

C @reboot /home/ann/start.sh

Question 2

A # Monthly report, 1st at 9 am

B 0 9 1 * * /home/ann/report.sh

C # Weekly clean, Mon at 5 am

D 0 5 * 1 * /home/ann/clean.sh

Question 3

A crontab -l

B 3 0 * * 0 /home/ann/backup.sh

C # Runs Sunday at 3:00 am

Question 4

A schtask /query /tn Backup

B schtasks /run /tn Backup

C schtasks /end /tn Backup

Question 5

A # Daily backup at 1:15 am

B # min hour day month weekday

C 15 1 1 * * python3 backup.py

Answer Key

Scheduling a task to run automatically

Section A: Quick Questions

A — Runs a command or script at set times without a person starting it

A — Windows Task Scheduler

B — Run every day at 2:30 am

B — 0 23 * * * /home/backup.sh

A — The backup runs every night even if the user forgets

Section B: Match the Pairs

0 2 * * * python3 backup.py → A cron entry that runs backup.py automatically at 2:00 am every day

@reboot /home/user/sync.sh → A cron entry that runs sync.sh each time the computer starts up

Run a backup script automatically at 11:30 pm every Friday using a cron expression → 30 23 * * 5 /home/user/backup.sh

Windows Task Scheduler can create a daily task that starts a backup program from the command line → schtasks /create /tn Backup /tr backup.bat /sc daily /st 22:00

2 0 * * * /home/user/backup.sh (meant to run at 2:00 am) → The minute and hour fields are in the wrong order. This runs at 12:02 am, not 2:00 am. It should be 0 2 * * *.

0 2 * * backup.sh → Only four time fields are given, so cron reads backup.sh as the fifth time field. A cron entry needs five time fields, such as 0 2 * * * backup.sh.

Section C: Definitions

cron — A scheduler that runs a command or script at set times without a person starting it, such as a nightly backup. Windows Task Scheduler does the same job.

Section D: Fill in the Blanks

# Run backup.sh at 2am every day
0 2 * * * /home/ava/backup.sh

# Run backup.sh once at start-up
@reboot /home/ava/backup.sh

# Edit your list of scheduled cron jobs
crontab -e

# Windows Task Scheduler: run every day
schtasks /create /tn "Backup" /sc daily

# Run backup.sh every day at 6:30pm
30 18 * * * /home/ava/backup.sh

Section E: Spot the Error

A — A cron expression needs five time fields (minute, hour, day of month, month, weekday). This line has only four, so cron reads the path as a field. It should be 0 2 * * * before the command.

D — The fourth field is the month, so this job would only run in January. Monday is set in the fifth (weekday) field, so the line should be 0 5 * * 1.

B — Cron puts the minute first and the hour second. 3 0 means 12:03 am, not 3:00 am. It should be 0 3 * * 0.

A — The Windows Task Scheduler command line tool is called schtasks, with an s on the end. The line should be schtasks /query /tn Backup.

C — The third field is the day of the month. Putting 1 there makes the backup run only on the 1st of each month. Use * so it runs every day: 15 1 * * *.