4

In bash, when I write this line

new_line="new\nline"

I get this as expected:

echo $new_line
new\nline

And this also works as expected:

echo -e $new_line 
new
line

as it says in a manual: -e enable interpretation of backslash escapes However, this doesn't give me an interpreted \n new line character:

cur_log=$(who)
echo -e $cur_log
myuser pts/0 2017-01-19 07:10 (:0) myuser pts/1 2017-01-19 09:26 (:0) myuser pts/4 2017-01-19 09:14 (:0)

I thought that there is no new line character but if I write:

echo "$cur_log"

I get new line character interpreted.

myuser  pts/0        2017-01-19 07:10 (:0)
myuser  pts/1        2017-01-19 09:26 (:0)
myuser  pts/4        2017-01-19 09:14 (:0)

Why doesn't echo -e $cur_log interpret new line character but `echo -e $new_line does?

5

The reason is in your first variable (new_line), there is only an escape sequence (i.e. \n = backslash followed by n) which is passed unchanged to echo, while in the second one (cur_log), there are actual newlines which are stripped out by the shell being part of the IFS variable.

A new line is, under Unix/Linux, a single character which ASCII code is 10 (line-feed). When a file containing this character is displayed on screen, it is converted into two characters, carriage-return plus line feed (CR-LF), 10 + 13. When an editor like gedit is opens such a file, it stores each line separately. Linefeed is only used to detect the separation between two contiguous lines. \n is made of two characters, ASCII 92 + 110. If you edit a file containing occurrences of \n these two characters will be left unchanged and displayed as is, unlike real newlines.

  • I thougt that actual new lines are only lines with \n character – Hrvoje T Jan 19 '17 at 17:00
  • No, that's just a convention to represent new lines. – jlliagre Jan 19 '17 at 17:10
  • And if I write in vim text in two line how gedit will know that this file has two lines? Isn't hiden \n used there? – Hrvoje T Jan 19 '17 at 17:32

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.