Cannot seem to find an answer to this one online...
I have a string variable (externally sourced) with new lines "\\n"
encoded as strings.
I want to replace those strings with actual new line carriage returns. The code below can achieve this...
echo $EXT_DESCR | sed 's/\\n/\n/g'
But when I try to store the result of this into it's own variable, it converts them back to strings
NEW_DESCR=`echo $EXT_DESCR | sed 's/\\n/\n/g'`
How can this be achieved, or what I'm I doing wrong?
Here's my code I've been testing to try get the right results
EXT_DESCR="This is a text\nWith a new line"
echo $EXT_DESCR | sed 's/\\n/\n/g'
NEW_DESCR=`echo $EXT_DESCR | sed 's/\\n/\n/g'`
echo ""
echo "$NEW_DESCR"
No need for sed
, using parameter expansion :
$ foo='1\n2\n3'; echo "${foo//'\n'/$'\n'}"
1
2
3
With bash 4.4
or newer, you can use the E
operator in ${parameter@operator}
:
$ foo='1\n2\n3'; echo "${foo@E}"
1
2
3
Other answers contain alternative solutions. (I especially like the parameter expansion one.)
Here's what's wrong with your attempt:
In
echo $EXT_DESCR | sed 's/\\n/\n/g'
the sed command is in single quotes, so sed gets s/\\\\n/\\n/g
as is.
In
NEW_DESCR=`echo $EXT_DESCR | sed 's/\\n/\n/g'`
the whole command is in backticks, so a round of backslash processing is applied. That leads to sed getting the code s/\\n/\\n/g
, which does nothing.
A possible fix for this code:
NEW_DESCR=`echo $EXT_DESCR | sed 's/\\\\n/\\n/g'`
By doubling up the backslashes, we end up with the right command in sed.
Or (easier):
NEW_DESCR=$(echo $EXT_DESCR | sed 's/\\n/\n/g')
Instead of backticks use $( )
, which has less esoteric escaping rules.
Note: Don't use ALL_UPPERCASE
for your shell variables. UPPERCASE
is (informally) reserved for system variables such as HOME
and special built-in variables such as IFS
or RANDOM
.
This printf
would do the job by interpreting all escaped constructs:
printf -v NEW_DESCR "%b" "$EXT_DESCR"
-v
option will store output in a variable so no need to use command substitution here.
Problem with your approach is use of old back-ticks. You could do:
NEW_DESCR=$(echo "$EXT_DESCR" | sed 's/\\n/\n/g')
Assuming you're using gnu sed
as BSD sed
won't work with this approach.
Depending on what exactly you need it for:
echo -e $EXT_DESCR
might be all you need.
From echo man page:
-e enable interpretation of backslash escapes
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