I need to write a script that will add a line to a text file if Enter is pressed.

But, if Ctrl+D is pressed, I need to exit that loop in the bash.

touch texttest.txt
while true; do
    read LINE;
    if [ "$LINE" == "^D" ]; then
            echo "$LINE" >> texttest.txt

Currently have something like this but cannot figure out how I am do exit the while loop when Ctrl+D is pressed instead of Enter.


You're overthinking it. All you need is this:

cat > texttest.txt

Cat will read from STDIN if you've not told it different. Since it's reading from STDIN, it will react to the control character Ctrl+D without your having to specify it. And since Ctrl+D is the only thing that will finish the cat subprocess, you don't even need to wrap it in a loop.


The following would do:

while read -r LINE ; do
  echo "$LINE" >> texttest.txt
  1. you don't need to touch the file first
  2. you don't need to initialize the LINE variable
  3. Ctrl+D closes stdin, which makes read exit with non-null (false) exit code
  • whoever edited my answer, I disagree. – artm Oct 13 '14 at 6:36

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