How can I have a newline in a string in sh?

sh
Juan A. Navarro picture Juan A. Navarro · Jun 9, 2010 · Viewed 319.2k times · Source

This

STR="Hello\nWorld"
echo $STR

produces as output

Hello\nWorld

instead of

Hello
World

What should I do to have a newline in a string?

Note: This question is not about echo. I'm aware of echo -e, but I'm looking for a solution that allows passing a string (which includes a newline) as an argument to other commands that do not have a similar option to interpret \n's as newlines.

Answer

amphetamachine picture amphetamachine · Jul 6, 2010

If you're using Bash, the solution is to use $'string', for example:

$ STR=$'Hello\nWorld'
$ echo "$STR" # quotes are required here!
Hello
World

If you're using pretty much any other shell, just insert the newline as-is in the string:

$ STR='Hello
> World'

Bash is pretty nice. It accepts more than just \n in the $'' string. Here is an excerpt from the Bash manual page:

   Words of the form $'string' are treated specially.  The word expands to
   string, with backslash-escaped characters replaced as specified by  the
   ANSI  C  standard.  Backslash escape sequences, if present, are decoded
   as follows:
          \a     alert (bell)
          \b     backspace
          \e
          \E     an escape character
          \f     form feed
          \n     new line
          \r     carriage return
          \t     horizontal tab
          \v     vertical tab
          \\     backslash
          \'     single quote
          \"     double quote
          \nnn   the eight-bit character whose value is  the  octal  value
                 nnn (one to three digits)
          \xHH   the  eight-bit  character  whose value is the hexadecimal
                 value HH (one or two hex digits)
          \cx    a control-x character

   The expanded result is single-quoted, as if the  dollar  sign  had  not
   been present.

   A double-quoted string preceded by a dollar sign ($"string") will cause
   the string to be translated according to the current  locale.   If  the
   current  locale  is  C  or  POSIX,  the dollar sign is ignored.  If the
   string is translated and replaced, the replacement is double-quoted.

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