Difference between revisions of "Scripting - Chapter 4: Conditions"
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== Conditions? Can one eat it? == | == Conditions? Can one eat it? == | ||
| − | You'd have to be very hungry but | + | You'd have to be very hungry, but why not? More seriously, a condition will allow you to order your script to do different things according to '''a test'''. For example, the value of a variable. |
== Some examples will make it easier to understand == | == Some examples will make it easier to understand == | ||
| Line 22: | Line 22: | ||
POL_SetupWindow_menu "What's for dinner?" "Tonight's menu" "Carrots Potatoes French-fries" " " | POL_SetupWindow_menu "What's for dinner?" "Tonight's menu" "Carrots Potatoes French-fries" " " | ||
if [ "$APP_ANSWER" = "Carrots" ] | if [ "$APP_ANSWER" = "Carrots" ] | ||
| + | then | ||
POL_SetupWindow_message "I'm on a hunger strike" "Tonight's menu" | POL_SetupWindow_message "I'm on a hunger strike" "Tonight's menu" | ||
else | else | ||
| Line 47: | Line 48: | ||
What this code does should be clear enough after seeing the previous examples. | What this code does should be clear enough after seeing the previous examples. | ||
| + | |||
| + | {{Info|In Bash, you can use either single-quotes ('), aka '''apostrophe''', or double-quotes ("), aka '''quote'''. We highly recommend, as a standard, to use double-quotes ("), aka '''quote''', so that you can use apostrophe in your string, if needed. Though, it is also preferred not to use contractions (which require an apostrophe, or '''single-quote''' (')) at all to avoid this situation altogether. The choice is yours; choose whichever is the cleanest, easiest-to-read, most-concise code.}} | ||
'''Previous:''' [[Scripting - Chapter 3: Variables|Chapter 3: Variables]] | '''Previous:''' [[Scripting - Chapter 3: Variables|Chapter 3: Variables]] | ||
Latest revision as of 23:58, 8 July 2016
Conditions? Can one eat it?
You'd have to be very hungry, but why not? More seriously, a condition will allow you to order your script to do different things according to a test. For example, the value of a variable.
Some examples will make it easier to understand
A test, with no action taken in case of failure:
POL_SetupWindow_menu "What's for dinner?" "Tonight's menu" "Carrots Potatoes French-fries" " " if [ "$APP_ANSWER" = "Carrots" ] then POL_SetupWindow_message "Let's eat" "Tonight's menu" fi
The message "let's eat" will only appear if the user chooses Carrots.
A test, with some action in case of failure:
POL_SetupWindow_menu "What's for dinner?" "Tonight's menu" "Carrots Potatoes French-fries" " " if [ "$APP_ANSWER" = "Carrots" ] then POL_SetupWindow_message "I'm on a hunger strike" "Tonight's menu" else POL_SetupWindow_message "Can I have a second helping?" "Tonight's menu" fi
The message "I'm on a hunger strike" will only be displayed if the user chooses Carrots. Otherwise the message "Can I have a second helping?" will be displayed.
Threefold test, with no action in case of failure:
POL_SetupWindow_menu "What do you want to eat tonight?" "Tonight's menu" "Carrots Potatoes French-fries" " "
if [ "$APP_ANSWER" = "French-fries" ]
then
POL_SetupWindow_message "I love french fries" "Tonight's menu"
elif [ "$APP_ANSWER" = "Potatoes" ]
then
POL_SetupWindow_message "I agree to eat potatoes tonight" "Tonight's menu"
elif [ "$APP_ANSWER" = "Carottes" ]
then
POL_SetupWindow_message "I do not like carrots" "Tonight's menu"
fi
What this code does should be clear enough after seeing the previous examples.
In Bash, you can use either single-quotes ('), aka apostrophe, or double-quotes ("), aka quote. We highly recommend, as a standard, to use double-quotes ("), aka quote, so that you can use apostrophe in your string, if needed. Though, it is also preferred not to use contractions (which require an apostrophe, or single-quote (')) at all to avoid this situation altogether. The choice is yours; choose whichever is the cleanest, easiest-to-read, most-concise code.
Previous: Chapter 3: Variables
Next: Chapter 5: Wine
