Write a shell script that takes in a variable from the terminal? (~$ command variable)

Question

I am writing a shell script that takes in a time (in minutes) and opens an online egg timer set for that amount.

#!/bin/bash
#Opens http://e.ggtimer.com/TIMEmin where TIME = number of minutes
TIME=5
xdg-open http://e.ggtimer.com/"$TIME"min

When I run the above script it opens the web page http://e.ggtimer.com/5min I would like to set the time from the terminal. For example:

eggtimer 10

Would open http://e.ggtimer.com/10min

Thank you!

The first command line argument is $1 so TIME=$1 or just put $1 in your URL. — Joseph R., May 02 '14 at 00:07
@JosephR. Even if it seems too simple to you: Make that an answer so that it can be accepted and the question get marked done. — Hauke Laging, May 02 '14 at 00:18
I swear I didn't even see your comment, I was already thinking of my ${VAR:-defaultval} post when I wrote it, just saw the commentary now. — slm, May 02 '14 at 00:22
@slm No worries. My previous comment was sincere, not passive aggressive :) — Joseph R., May 02 '14 at 00:29

score 5 · Accepted Answer · edited Apr 13 '17 at 12:36

If you use the following feature of Bash variables where they're used if they have a value otherwise a default value is used instead you can code up your example like so:

$ more etimer.bash 
#!/bin/bash
#Opens http://e.ggtimer.com/TIMEmin where TIME = number of minutes
TIME=${1:-5}
xdg-open http://e.ggtimer.com/"$TIME"min

This will use an argument that's passed into etimer.bash if one is provided, otherwise will use 5 minutes.

Examples

$ ./etimer.bash

Results in this URL: http://e.ggtimer.com/5min

$ ./etimer.bash 10

Results in this URL: http://e.ggtimer.com/10min

References

Using "${a:-b}" for variable assignment in scripts

Write a shell script that takes in a variable from the terminal? (~$ command variable)

1 Answers1

Examples

References