I need to pass a list of sorted, quoted FLAC file names to SoX for concatenation but am having trouble getting sort to work the way I expect it to.

If I use:

find . -maxdepth 1 -type f -iname "*.flac" | sort

I get exactly what I expect:

./02-Both Sides Now.flac
./03-Solitary Man.flac
./04-Holly Holy.flac
./05-Cherry Cherry.flac
./06-Kentucky Woman.flac
./07-Sweet Caroline.flac
./08-Thank the Lord for the Nightime.flac
./09-And the Singer Sings His Song.flac
./10-Brother Loves Traveling Salvation Show.flac

However, I can't really use that for what I'm doing since I need a quoted list with no newlines. I know -printf can do that for me, but when I try:

find . -maxdepth 1 -type f -iname "*.FlAc" -printf "\"%p\" " | sort

I wind up with a list of file names that are quoted and separated by a single space (good!) but they aren't sorted (bad!). Or at least they aren't sorted the way I expect them to be:

"./08-Thank the Lord for the Nightime.flac" "./03-Solitary Man.flac" "./09-And the Singer Sings His Song.flac" "./05-Cherry Cherry.flac" "./06-Kentucky Woman.flac" "./10-Brother Loves Traveling Salvation Show.flac" "./07-Sweet Caroline.flac" "./02-Both Sides Now.flac" "./01-Lordy.flac" "./04-Holly Holy.flac"

Maybe even weirder, if I just for the sake of testing use the same code but add a newline:

find . -maxdepth 1 -type f -iname "*.FlAc" -printf "\"%p\" "\\n | sort

The sort works even if the output is back to not being what I need:

"./02-Both Sides Now.flac" 
"./03-Solitary Man.flac" 
"./04-Holly Holy.flac" 
"./05-Cherry Cherry.flac" 
"./06-Kentucky Woman.flac" 
"./07-Sweet Caroline.flac" 
"./08-Thank the Lord for the Nightime.flac" 
"./09-And the Singer Sings His Song.flac" 
"./10-Brother Loves Traveling Salvation Show.flac"

This is under Ubuntu 18.04.1

  • Do you have to use find here, for the recursion? Or are all the desired files in the same directory? (I ask, given the -maxdepth 1 and the sample output indicating the same directory)
    – Jeff Schaller
    Jan 20, 2019 at 1:48
  • 1
    I think what you're overlooking is that sort sorts lines (or, with GNU sort -z, null-delimited elements) - it should be no surprise that it doesn't sort filenames when they're all on a single line Jan 20, 2019 at 1:58
  • 2
    If you a) are using GNU sed and b) you really need to find your files recursively, you can use this: find . -iname '*.flac' -print0 | sort -z | xargs -0 sox ... instead of messing with quoting and unquoting.
    – user313992
    Jan 20, 2019 at 2:00
  • @mosvy I was just experimenting with that idea; that seems like a good additional answer!
    – Jeff Schaller
    Jan 20, 2019 at 2:00
  • If you're trying to collect filenames to pass to SoX as command-line arguments, you do not want to put quotes around them. Quotes are parsed only when they're actually part of the command, not when they're in date (e.g. from a variable or command substitution). See here for an example. Jan 20, 2019 at 4:28

1 Answer 1


If the files are all in the same directory, and you want to pass a list of sorted filenames to sox, then the bash shell could do that directly:

shopt -s nocaseglob
sox *.flac

The nocaseglob shell option allows the wildcard to pick up foo.FLAC, foo.Flac, foo.flaC, etc. The wildcard expands to an alphabetically sorted list, much like a bare sort would. It would, for example, put 9-file.flac after any filename that started with 8.

Thanks to @mosvy for a simplification of the above bash-ism into a wildcard that should work with any shell:

sox *.[Ff][Ll][Aa][Cc]

The brackets allow any combination of upper- and lower-case letters in the "flac" extension, in order to match what your find ... -iname "*.FlAc" was doing.

  • 2
    no need for nocaseglob; sox *.[fF][lL][aA][cC] will do just fine, in any shell.
    – user313992
    Jan 20, 2019 at 1:57
  • Thank you everyone. sox *.[fF][lL][aA][cC] looks like it works while printf '%s\n' *.[Ff][Ll][Aa][Cc] looks like it gives me what I need to double-check that the order is correct.
    – atrocity
    Jan 20, 2019 at 5:15

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