Passing a tab character as a command line argument in Java
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The tab that you defined in code is a single-character string (since "t" is an escape sequence). From the command line you get a two-characters string, as bash doesn't handle "t" as the tab character.
To pass that from command line, you can use echo -e which supports escape sequences like t (or n and a few others):
$ java Main "$(echo -en 't')"
If you pass 't' or "t" on your command line, it causes a literal backslash followed by a t to be passed to your command:
$ echo -n 't' | xxd
00000000: 5c74 t
$ echo -n "t" | xxd
00000000: 5c74 t
You can type a tab on your command line using Ctrl-v then Tab:
$ echo -n ' ' | xxd
00000000: 09 .
(That wide space is a tab character, not lots of spaces).
To pass a tab as an argument from bash, you can do any of the following:
mycommand $'argtcontainingttabs'
Which works because $'' in bash interprets escape sequences.
mycommand 'arg ctrl-vtab containing ctrl-vtab tabs'
Which works because ctrl-v causes the next character typed to be inserted literally rather than being interpreted.
mycommand "$(printf 'argtcontainingttabs')"
Which works, in bash and other shells, because printf interprets backslash-escaped characters in its first argument.
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