What are <84>, <82>?

UNIX for Beginners Q & A
1

Hi,
I am editing a text file in VI and am occasionally seeing "characters" <82> and <84>. in my VIM they are marked in the same way the EOL character ^M is.
When running:cat filename.txt
the characters seem to be read as a linefeed.
How do I search and replace these characters in VI.
What are they?
I do know that for the EOL character I press CTRL-V and "Enter" to get ^M.

Is there a list of these characters somewhere. <82> does not seem to be "T"

2

The <hex_digits> (in blue if you're using a color terminal is the hexadecimal value of a byte that is not part of a valid character in your current locale.

You can translate the hex value(s) to octal using printf . And then you can use tr to delete those characters. For example, if vi shows you <82> , <84> , and <fe> ; you could use:

printf '\\%03o\n' 0x82 0x84 0xfe

which would give you:

\202
\204
\376

and then you could use:

LC_ALL=C tr -d '\202\204\376' < input_file > output_file

to remove all occurrences of those three byte values from input_file with the updated contents stored in the file output_file .

3

Hello CaptSutter,

Welcome to forums, I hope you will enjoy learning and sharing knowledge here. Coming to your question. You could see control M characters by doing cat -v Input_file and if you want to remove control M characters from Input_file then use following command too on same(if your objective is to only remove control M characters).

tr -d '\r' < Input_file > temp_file && mv temp_file Input_file

Let me know if you have any queries on same.

Thanks,
R. Singh

4

Depending on the locale, those chars should not come alone. In e.g. UTF-8 encoding, they'll be accompanied by a leading C2 (hex), which then should be removed as well.