Reading files line by line in by using for loop bash script [duplicate]

Question

Say for example I have a file called "tests",it contains

a
b
c
d

I'm trying to read this file line by line and it should output

a
b
c
d

I create a bash script called "read" and try to read this file by using for loop

#!/bin/bash
for i in ${1}; do //for the ith line of the first argument, do...
   echo $i  // prints ith line
done

I execute it

./read tests

but it gives me

tests

Does anyone know what happened? Why does it print "tests" instead of the content of the "tests"? Thanks in advance.

Answer 1

#!/bin/bash
while IFS= read -r line; do
  echo "$line"
done < "$1"

This solution can handle files with special characters in the file name (like spaces or carriage returns) unlike other responses.

Answer 2

You need something like this rather:

#!/bin/bash
while read line || [[ $line ]]; do
  echo $line
done < ${1}

what you've written after expansion will become:

#!/bin/bash
for i in tests; do
   echo $i
done

if you still want for loop, do something like:

#!/bin/bash
for i in $(cat ${1}); do
   echo $i
done