Bash Shell Scripting - return key/Enter key
I need to compare my input with Enter/Return key...
read -n1 key if [ $key == "\n" ] echo "@@@" fi
But this is not working.. What is wrong with this code
Several issues with the posted code. Inline comments detail what to fix:
#!/bin/bash # ^^ Bash, not sh, must be used for read options read -s -n 1 key # -s: do not echo input character. -n 1: read only 1 character (separate with space) # double brackets to test, single equals sign, empty string for just 'enter' in this case... # if [[ ... ]] is followed by semicolon and 'then' keyword if [[ $key = "" ]]; then echo 'You pressed enter!' else echo "You pressed '$key'" fi
read reads a line from standard input, up to but not including the new line at the end of the line. -n specifies the maximum number of characters, forcing read to return early if you reach that number of characters. It will still end earlier however, when the Return key is pressed. In this case, its returning an empty string - everything up to but not including the Return key.
You need to compare against the empty string to tell if the user immediately pressed Return.
read -n1 KEY if [[ "$KEY" == "" ]] then echo "@@@"; fi
I'm adding below code just for reference if someone will want to use such solution containing countdown loop.
IFS='' echo -e "Press [ENTER] to start Configuration..." for (( i=10; i>0; i--)); do printf "\rStarting in $i seconds..." read -s -N 1 -t 1 key if [ "$key" = $'\e' ]; then echo -e "\n [ESC] Pressed" break elif [ "$key" == $'\x0a' ] ;then echo -e "\n [Enter] Pressed" break fi done
Also it is good idea to define empty $IFS (internal field separator) before making comparisons, because otherwise you can end up with " " and "\n" being equal.
So the code should look like this:
# for distinguishing " ", "\t" from "\n" IFS= read -n 1 key if [ "$key" = "" ]; then echo "This was really Enter, not space, tab or something else" fi