UNIX for Dummies Questions & Answers

Hi ,
I am working on Linux, with ksh93 installed.

The following statement
echo \\n

just prints

\n on this shell.

However on pdksh
echo \\n gives a blank new line as a output.

What is the correct way of printing a new line character on the ksh93?

Hi,

You could try:

Code:

echo -e \\n

However, the behaviour of echo is system dependent, so in general it would be better to use

Code:

printf "\n\n"

instead...

Thanks..
I have another question .. I am trying to assign this value to another variable:
${fetched_value} contains the string with \n

So following prints the value correctly

Code:

echo -e   ${fetched_value} " My manipulated value "

SYS_P8708 SYS_P8564 SYS_P8500 60
SYS_P8709 SYS_P8565 SYS_P8501 61

however when I try to manipulate this variable to something like:

Code:

fetched_value=`echo -e ${fetched_value}`

i get the following output

Code:

SYS_P8708 SYS_P8564 SYS_P8500 60 SYS_P8709 SYS_P8565 SYS_P8501 61

What am I doing wrong here?

Hi, what exactly is you input and your output, what did you try, and what is your desired output?

This should be regarded as a bug in pdksh, the behavior of ksh93 is absolutely definitely correct.

You probably know that "\" is used to escape characters with a special meaning to the shell. For instance "$var" would be parsed the following way: the shell sees "$", which means "take the word after that and look for a variable with that name ("var"), then replace the "$" and the word following it with the contents of this variable". Because there is no way to literally use a "$" this way we can use "\$" to tell the shell not to regard this special behavior of "$" and treat it like a normal character.

Example:

Code:

var="abcde"
echo $var           # output: "abcde"
echo \$var          # output: "$var"

For the same reason we need to escape the backslash itself, because it also has a special meaning - to escape other characters. Therefore: to literally write a backslash we have to precede it by a - backslash!

Look at your statement now in light of this explanation, the reason why the output has to be "\n" should be clear by now.

Moderator's Comments:

Please open another thread for this. We want our threads to deal with only one problem at a time to make our database of problems already dealt with as clear as possible. Thanks.

I hope this helps.

bakunin