45 lines
1.9 KiB
Bash
45 lines
1.9 KiB
Bash
function description() {
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echo -e "Functions are a special type of program that you can define right inside bash." \
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"They are very nifty inside Bash scripts."\
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"They are blocks of commands," \
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"much like normal scripts you might write," \
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"except they don't reside in separate files," \
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"and they don't cause a separate process to be executed." \
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"However, they take arguments just like scripts. Take this for example:${YELLOW}"
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echo " $ function sum() {"
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echo ' > echo "$1 + $2 = $(($1 + $2))'
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echo " > }"
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echo -e "${NORMAL}"
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echo -e "${CYAN}Note:${NORMAL} while most commands you run terminate at the first new line," \
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"Bash is perfectly capable of reading multiline input and determining" \
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"when the input is going to be multiline (or should be anyways)."
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echo ""
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echo -e "This will do absolutely nothing when run." \
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"This is because it has only been stored in memory," \
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"much like a variable, but it has not yet been called." \
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"To run the function, you would do this:${YELLOW}"
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echo " $ sum 1 4"
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echo " 1 + 4 = 5"
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echo -e "${NORMAL}"
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echo "Amazing! We now have a basic calculator," \
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"and potentially a more economic replacement for a five year-old."
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echo ""
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echo -e "Inside functions you get access to a special program: '${YELLOW}return${NORMAL}'." \
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"It can be used to make specify the functions exit value by passing" \
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"it as an argument." \
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"If you do not use return, the function's exit value will be the same as the" \
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"last executed commands exit value."
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echo ""
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echo -e "${BLUE}# Find a way to execute a command with an exit value of 231.${NORMAL}"
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}
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function hint() {
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echo "function a() { return 231; }; a"
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}
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function validate() {
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if [ "$BASHTUTOR_R" == 231 ]; then
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return 1
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fi
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}
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