Looping file contents line by line in BASH

Question

I have a file called installer.txt which will contain a line by line of URLs of .tar.gz files like:

http://oscargodson.com/projects/example1.tar.gz http://oscargodson.com/projects/anotherexample.tar.gz http://oscargodson.com/projects/onemore.tar.gz

And I tried:

#!/bin/bash file = `cat installs.txt` for word in file; do echo $word done

But my output is like:

Oscars-MacBook-Air:Desktop oscargodson$ ./test.sh =: cannot open `=' (No such file or directory) http://oscargodson.com/projects/example1.tar.gz: cannot open `http://oscargodson.com/projects/example1.tar.gz' (No such file or directory) http://oscargodson.com/projects/anotherexample.tar.gz: cannot open `http://oscargodson.com/projects/anotherexample.tar.gz' (No such file or directory) http://oscargodson.com/projects/onemore.tar.gz: cannot open `http://oscargodson.com/projects/onemore.tar.gz' (No such file or directory) file

It should output each line, or, so i thought. Ideas?

Sodved · Accepted Answer · 2011-11-13 00:16:02Z

1

You errors are actually being generated by the assignment statement. You cant have spaces around your assignment. And its good practice to always quote the rhs. So what you want is

#!/bin/bash -u file="$(cat installs.txt)" for word in $file; do echo $word done

I also changed you back qoutes to $( ) as this is the recommended way and I think its easier to read too

answered Nov 13, 2011 at 0:16

Sodved

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4 Comments

Oscar Godson Over a year ago

thanks. Coming from a JavaScript background mainly and some rails, this syntax is quite strange to me :)

Gordon Davisson Over a year ago

He was also missing the $ when using file -- I see you fixed that as well.

Oscar Godson Over a year ago

Also, whats the -u mean in the shebang? Googled it, but no avail.

Sodved Over a year ago

The -u means the script will print an error if you reference an unset variable. Very useful for catching typos. e.g. if you accidentally had echo $wrod it woulf just print blank lines. But with the -u it would print an error message saying wrod is an undefined variable

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