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From: Geir Hauge <geir.hauge@gmail.com>
Newsgroups: gnu.bash.bug
Subject: Re: bash displays strange characters after base64 decoding
Date: Fri, 7 Aug 2015 15:08:03 +0200
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Approved: bug-bash@gnu.org
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Cc: bug-bash@gnu.org, bash@packages.debian.org
To: Valentin Schmidt <vsch@posteo.org>
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On Thu, Aug 06, 2015 at 07:45:53PM +0200, Valentin Schmidt wrote:
> Bash displays strange characters (including command prompt) (see attached
> png file) after the execution of the base64 (GNU coreutils 8.21) command
> like described as follows:
> base64 -d base64.txt

Xterm has some escape sequences that switch between a second character
set, where many of the ascii letters become line drawing characters
instead. 

Try the following:

    printf %b '\e(0' {a..z} '\n' '\e(B' {a..z} '\n'

This prints the 26 lowercase ascii letters in the second character set,
entered by the sequence ESC ( 0, followed by the same line after
switching back, with the sequence ESC ( B. In a Gnome Terminal on Ubuntu
I get the following output from the above:

    ▒␉␌␍␊°±␤␋┘┐┌└┼⎺⎻─⎼⎽├┤┴┬│≤≥
    abcdefghijklmnopqrstuvwxyz

Sven Mascheck has written a bit about this fun feature here:
http://www.in-ulm.de/~mascheck/various/alternate_charset/

-- 
Geir Hauge