In a directory size 80GB with approximately 700,000 files, there are some file names with non-English characters in the file name. Other than trawling through the file list laboriously is there:

  • An easy way to list or otherwise identify these file names?
  • A way to generate printable non-English language characters - those characters that are not listed in the printable range of man ascii (so I can test that these files are being identified)?

5 Answers 5


Assuming that "foreign" means "not an ASCII character", then you can use find with a pattern to find all files not having printable ASCII characters in their names:

LC_ALL=C find . -name '*[! -~]*'

(The space is the first printable character listed on http://www.asciitable.com/, ~ is the last.)

The hint for LC_ALL=C is required (actually, LC_CTYPE=C and LC_COLLATE=C), otherwise the character range is interpreted incorrectly. See also the manual page glob(7). Since LC_ALL=C causes find to interpret strings as ASCII, it will print multi-byte characters (such as π) as question marks. To fix this, pipe to some program (e.g. cat) or redirect to file.

Instead of specifying character ranges, [:print:] can also be used to select "printable characters". Be sure to set the C locale or you get quite (seemingly) arbitrary behavior.


$ touch $(printf '\u03c0') "$(printf 'x\ty')"
$ ls -F
dir/  foo  foo.c  xrestop-0.4/  xrestop-0.4.tar.gz  π
$ find -name '*[! -~]*'       # this is broken (LC_COLLATE=en_US.UTF-8)
... (a lot more)
$ LC_ALL=C find . -name '*[! -~]*'
$ LC_ALL=C find . -name '*[! -~]*' | cat
./x y
$ LC_ALL=C find . -name '*[![:print:]]*' | cat
./x y
  • 1
    Be aware that you have file names that are using foreign character sets that are incompatible with UTF-8 or ASCII. In those cases, you may see question marks instead of characters.
    – Lekensteyn
    Commented Jan 17, 2014 at 11:23
  • 1
    +1, but I would use LC_ALL=C instead of LC_COLLATE=C as it's doesn't make much sense to set LC_COLLATE to C without setting LC_CTYPE and to make sure it still works even when the LC_ALL variable is in the environment. Commented Jan 17, 2014 at 11:47
  • If SPC is printable, then what about TAB and LF which are also typically found in text files? Commented Jan 17, 2014 at 11:56
  • 1
    Thanks - this found six files, which had long hyphen, short hyphen and a variant of single quote. These had all originated from MS Word. No difference in the files listed between LC_ALL and LC_COLLATE. LC_COLLATE displayed the non-ASCII chars correctly whereas LC_ALL displayed ??? instead. Excellent answer!
    – suspectus
    Commented Jan 17, 2014 at 12:35
  • 1
    @suspectus I updated by answer based on suggestions from Stephane. For LC_COLLATE and LC_CTYPE, see also the find(1) manpage.
    – Lekensteyn
    Commented Jan 17, 2014 at 12:44

If you translate each file name using tr -d '[\200-\377]' and compare it with the original name, then any file names that have special characters will not be the same.

(The above assuming that you mean non-ASCII with foreign)

  • 3
    That also removes [ and ] in most tr implementations. Commented Jan 17, 2014 at 11:21
  • Yes - it did remove [ and ] on my system.
    – suspectus
    Commented Jan 17, 2014 at 11:57
  • +1 - the solution did find all the (six) file names with non ASCII symbols (in addition to the [ and ]s). thanks.
    – suspectus
    Commented Jan 17, 2014 at 12:26

You can use tr to delete any foreign character from a filename and compare the result with the original filename to see if it contained foreign characters.

find . -type f > filenames
while read filename; do
      stripped="$(printf '%s\n' "$filename" | tr -d -C '[[:alnum:]][[:space:]][[:punct:]]')"
      test "$filename" = "$stripped" || printf '%s\n' "$filename"; 
done < filenames
  • 5
    that is a nice extension to my answer, but it is too simple, file names can have newlines in them and then your script will not work
    – Timo
    Commented Jan 17, 2014 at 11:16
  • 1
    If you want to post-process find output, use NUL-terminated output/input as shown in this answer.
    – Lekensteyn
    Commented Jan 17, 2014 at 11:20

The accepted answer is helpful, but if your filenames are already in the encoding specified in LANG/LC_CTYPE, it's better to just do:

LC_COLLATE=C find . -name '*[! -~]*'

Character classes are affected by LC_CTYPE, but the above command does not use character classes, only ranges, so LC_CTYPE just prevents the unusual characters from being replaced by question marks.


The other answers are usable, but the following gives better visual identification of the exact "offending" characters:

find | GREP_COLORS='mt=05;07;31' LC_ALL=C grep --color=always -E '[^[:print:]]'
  • find | LC_ALL=C ack --color-match="blink reverse red" '[^[:print:]]' also works, if you have ack installed.
    – Paxsali
    Commented Oct 5, 2023 at 22:11

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