I have a cron job ...
/bin/sh /usr/local/maint/update-wp-sites 2>&1 > /usr/local/maint/output/update-wp-sites.$(date +"\%F_\%H\%M\%S").txt
It works great.
Here's the code for update-wp-sites:
red='\033[0;31m'
color_off='\033[0m'
echo -e "$red updating wp core $color_off"
wp core update
But the output in the update-wp-sites.$(date ...) file specified above looks like this:
-e updating wp core
Success: WordPress is up to date.
Why is "-e" appearing?
Use printf (which is Posix standard) instead of the non-standard echo -e:
red='\033[0;31m'
color_off='\033[0m'
printf "${red}%s${color_off}\n" "updating wp core"
wp core update
The same applies to echo -n.
Posix does not specify any command-line options for echo, and a Posix-compliant echo simply prints all of its arguments verbatim, including the ones which look like command-line options.
The common (but not universal) extensions to echo can really get in the way: there is no portable way to use them nor to suppress them (in case you wanted to output something starting with -e, for example).
Better to stick with printf, which is a built-in on most shells, which has standardized behaviour, and which is cleanly extensible.