Reading in 3 lines of input-CodePudding

Lets say I have the following input in bash/linux

2
3
5

and I want to assign these lines to num1 num2 and num2 separately. How could I assign these variables? I know for sure it involves read but I don't know how to break apart what it reads.

Thanks!

CodePudding user response：

Since read reads a line (by default), you want 3 separate read commands:

read -r num1
read -r num2
read -r num3

You can read all the input into an array with the mapfile command.

mapfile -t nums
# then
echo "first:  ${nums[0]}"
echo "second: ${nums[1]}"
echo "third:  ${nums[2]}"

CodePudding user response：

run in bash $

needname() { i=0; while read num$i; do x=num${i}; echo "${!x}"; if [[ -z ${num}$i ]]; then break; fi;((i  )); done ; }

You can have a file (test.txt) with the content

Line1
Line2
Line3

And run

needname < test.txt

Or you can input it with a pipe

echo -en "line1\nline2\nline3\n"|needname
cat test.txt|needname

Or simply type them in by hand ending with a blank line

needname

Then > echo "$num0 $num1 etc"

You can put this function in a file script.sh and use it the same way