Kakasi kanji to roomaji converter encoding difficulties

Question

I am trying to use the Kakasi kanji/hiragana/katakana to roomaji converter, as an aid to learning kanji pronunciation within specific sentences. I am using command and parameters:

kakasi -Ja -Ha -Ka -Ea -s

For example, converting today's date gives:

$ echo "7月31日" | kakasi -Ja -Ha -Ka -Ea -s 
7 shin ?? 1 ka �

There is clearly a configuration error, that I think comes from the input encoding (UTF-8) not being correctly understood by the tool.

Could anybody with experience on this matter please advise on how to either tell kakasi to accept Unicode input, or suggest an alternative open-source tool for conversion that works better? (Please, no Windows software.)

Answer 1

Thanks to comments by @Earthliŋ and @blutorange (recognition where recognition is due), the combination of iconv with kakasi has finally worked. Initial convertion from Unicode to Shift-JIS is required, and performed using:

$ echo "7月31日" | iconv -f utf8 -t shift-jis | kakasi -Ja -Ha -Ka -Ea -s 

7 gatsu 31 nichi

Conversion back in the other direction is not needed when output is roumaji, since the basic characters have low ASCII values that are identical under all encodings. If necessary, conversion from Shift-JIS back to Unicode can be performed with:

$ echo "7月31日" | iconv -f utf8 -t shift-jis | kakasi -Ja -Ha -Ka -Ea -s | iconv -f shift-jis -t utf8

7 gatsu 31 nichi

For instance, to convert into Hiragana:

$ echo "7月31日" | iconv -f utf8 -t shift-jis | kakasi -JH -KH -Ea -s | iconv -f shift-jis -t utf8

7 がつ 31 にち

Update

As pointed out by @oals in the comments, newer versions of kakasi have the little documented parameters -iutf8 and -outf8 to specify Unicode encoding for either input or output. The above conversion to Hiragana can then be more efficiently performed using:

$ echo "7月31日" | kakasi -JH -KH -Ea -s -iutf8 -outf8

7 がつ 31 にち

Thanks for your help.