Read the files in shell script doesn't print out anything?

Question

I am trying to read a file from shell script line by line. Below is my file content -

hello=world

And below is my shell script that I have written -

#!/bin/bash

while read -r line; do
       echo "$line"
    done < test.txt

But somehow whenever I am running from my cygiwn terminal, I don't see any result printing out on the console -

I run it like this -

$ sh read.sh

And it doesn't print out anything. And I am not sure what wrong I am doing here.

Is there a newline at the end of that file? Many Windows editors don't put one. What happens with a two-line file? Also, does the script have Unix line endings? — Gilles 'SO- stop being evil', Dec 17 '13 at 00:21
Do we need a new line at the end of that file? After putting a new line in that file, it started working somehow.. — SSH, Dec 17 '13 at 00:22

score 4 · Accepted Answer · edited Apr 13 '17 at 12:36

In the unix world, a newline is a line terminator, not a line separator. A text file consists of a series of lines, each of which is terminated by a newline character. This is a linefeed character (character number 10, which can be represented as LF, ^J, \012, \x0a, \n, …). See What's the point in adding a new line to the end of a file?

In particular, every non-empty text file ends with a newline character. Windows sometimes works differently: in some applications, (but not all! Windows is not consistent), a CR LF sequence (carriage return, line feed, a.k.a. ^M^J, \015\012, \x0d\x0a, \r\n, …) separates lines, so a file that ends in CRLF is a file that ends in a blank line. So beware when you use a Windows editor to edit files that are meant to be used elesewhere:

They add this extra CR character before the newline character, which some unix applications (in particular shells) treat as an ordinary character, part of the line.
They make you believe that there's a blank line after the last newline character, whereas the last newline actually terminates the last line.

If a file is not empty and does not end in a newline, it isn't a well-formed unix text file. Some applications react by ignoring the last partial line, or by truncating it. That's what's happening here: you passed an incomplete text file to bash, and it's ignoring the last, incomplete line.

Read the files in shell script doesn't print out anything?

1 Answers1