First off, the standard disclaimer: I am pretty new at shell scripting, and my work at this point is mainly hacked-together ideas and pieces from other people's. Thank you in advance for your tolerance. :)

I am using Ubuntu Linux 7.10 Gutsy, which has the bash shell. I wrote a shell script that processes a file line by line to obtain path and file information. (Amarok .m3u playlist files, if that matters.) I use this structure to read the file in:

while read line
do a=$(($a+1));
(various processing commands go here)

Generally this works pretty well. Each line of the file winds up in the $line variable, and I can then work with it. The only weird and unexpected thing is that it collapses multiple spaces within the string. Since the strings contain file paths, this is a problem. So, for example, I might have this string in the file:

/remote/mp3/Eno, Brian/1  1.mp3

(This filename would result from Grip ripping a track titled "1 / 1" and stripping the forward slash).

During script execution, $line would wind up containing this:

/remote/mp3/Eno, Brian/1 1.mp3

Note that the double space has been condensed to a single space. Consequently nothing else I do with that string works, because it is no longer a correct path.

Why does this happen? Is there anything I can do about it? Is there a better way to process a file line by line in a script? Will our heroes escape from the tiger?

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Quote your variable: use "$line", not $line.

Quote your variable: use "$line", not $line.

Yes! Thank you, that worked. But why did it work?

You'll find the answer here.

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