Variables with spaces used in external command

Ruby
1

I’m a Ruby newb, so this is probably not coded in the most efficient
manner.

I’m trying to read through a list of folder and convert my wav files to
flac. The below code works with most files but some blow up and break at
spaces and I can’t figure out where my error is. This worked for most of
the files in my folder.

Dir.glob(".wav") do |filename|
mybasename = File.basename("#{filename}",’.’)
mybasename += “.flac”
puts “Calling avconv -i ‘#{filename}’ ‘#{mybasename}’”
%x[avconv -i ‘#{filename}’’#{mybasename}’]
end

My output looks like this:
Calling avconv -i ‘02-11 - When It’s Gone.wav’ ‘02-11 - When It’s
Gone.flac’
avconv version 9.16-6:9.16-0ubuntu0.14.04.1, Copyright © 2000-2014 the
Libav developers
built on Aug 10 2014 18:16:02 with gcc 4.8 (Ubuntu 4.8.2-19ubuntu1)
02-11 - When Its: No such file or directory

2

Did you type that out manually or copy it directly? You’re missing the
space between “’#{filename}’’#{mybasename}’”
There should be a space between the middle “’” characters.

You’re also using single quotes / apostrophes around a string containing
the same character. If you take “When it’s” and surround it with two “’”
characters, that’s 3 single quotes, making it terminate incorrectly.

3

Thanks for replying Joel.

Good eyes on the space, i’d been playing around with spacing thinking
that might be the cause, which it’s not.

What should I surround the variable with if it contains a apostrophes
and spaces ?

If I use double quotes, it breaks on spaces and the file-name ends up
being something like the example of “02-11 - When its” instead of "02-11

  • When It’s Gone.wav". Although this looks like an issue with the
    apostrophe rather than a space.

FCC

4

I’m no expert on on ubuntu, but if it won’t let you use double quotes,
have you tried escaping the space with “”? (or escaping the quote)

5

It seems like i’m at an impasse. If I don’t use a single quote, it
breaks on spaces and if I use a single quote it breaks on an apostrophe.

I don’t think I can escape anything since i’m passing the string to bash
to run avconv.

6

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7

Thanks for all you of your replies and suggestions. I think I’ve found
my solution.

Shellwords
http://www.rubydoc.org/stdlib1.9.3/libdoc/shellwords/rdoc/Shellwords.html

I’m not sure how I didn’t stumble on this before, but the shellescape
option looks like it should be used for all output you are trying to
pass to bash.