Looping through lines in a file in bash, without using stdin

Question

I am foxed by the following situation.

I have a file list.txt that I want to run through line by line, in a loop, in bash. A typical line in list.txt has spaces in.

Answer 1

You must open as a different file descriptor

while read p <&3; do
    echo "$p"
    echo 'Hit enter for the next one'
    read x
done 3< list.txt

Update: Just ignore the lengthy discussion in the comments below. It has nothing to do with the question or this answer.

Answer 2

I would probably count lines in a file and iterate each of those using eg. sed. It is also possible to read infinitely from stdin by changing while condition to: while true; and exit reading with ctrl+c.

line=0 lines=$(sed -n '$=' in.file)
while [ $line -lt $lines ]
do
    let line++
    sed -n "${line}p" in.file
    echo "Hit enter for the next ${line} of ${lines}."
    read -s x
done

AWK is also great tool for this. Simple way to iterate through input would be like:

awk '{ print  $0; printf "%s", "Hit enter for the next"; getline < "-" }' file

Answer 3

As an alternative, you can read from stderr, which by default is connected to the tty as well. The following then also includes a test for that assumption:

(
tty -s <& 2|| exit 1
while read -r line; do
    echo "$line"
    echo 'Hit enter'
    read x <& 2
done < file
)