Linux : How to check what kind of character code is used n’ change character code

install kcc and nkf

# apt-get install kcc # apt-get install nkf

check what character code is used

# kcc -c test.txt test.txt:       shift-JIS

or you can also check character code w/ nkf

# nkf --guess test.txt Shift_JIS

# cat test.txt how low ? [

change character code w/ nkf

convert Shift_JIS  into UTF-8 and overwrite

# nkf -w --overwrite test.txt

# nkf -g test.txt UTF-8

# cat test.txt how low ? ハロー

get things done.