UNIX for Dummies Questions & Answers

Q: Have you tested the snippet you just submitted?
So your conclusion?

cat prints input files (including stdin) to stdout. Use options like -A, -E, -T, -v to show control characters.
echo or (preferrably) printf print text and/or variables to stdout; pipe this through e.g. cat -A to see if a ^M is there.

This said, we are off topic considering the thread's title and so I will close the thread.
Up the the user to open a new threadregarding his new request...

Yes - if the system uses GNU-cat (or some other non-standard-conforming variant). POSIX-cat has only one valid option: "-u" for unbuffered operation.

Three ways to avoid and/or manage "^M" characters:

First, DO NOT WRITE YOUR SCRIPTS IN WINDOWS AND THEN FTP THEM TO UNIX! This is how the overwhelming majority of misplaced ^M-characters come to pass.

Second, open the file in questsion in vi and then enter: ":set list". This will display non-printable characters: "^I" is a tab, "^M" is a (Windows-style) line feed, "$" is a newline character, etc.. use the command ":set nolist" to switch back to normal display.

Third, control your variable definitions:

Code:

var='foo
bar'

will place a "^M" character between "foo" and "bar".

I hope this helps.

bakunin

Assuming standard TTY settings, the command:

Code:

var='foo
bar'

will place a <newline> (i.e., control-J or the C escape sequence '\n') between "foo" and "bar"; not a <carriage-return> (i.e., control-M or '\r').

Try:

Code:

var='foo
bar'
printf '%s\n' "$var" | od -bc

and you'll get:

Code:

printf '%s\n' "$v"|od -bc
0000000   146 157 157 012 142 141 162 012                                
           f   o   o  \n   b   a   r  \n

not:

Code:

0000000   146 157 157 015 142 141 162 012                                
           f   o   o  \r   b   a   r  \n