A cheap terminal trick


A cheap trick to highlight stuff in the terminal.

Sometimes a program has to output something and we want to be sure of what we are reading including spaces. I mean, there might be trailing spaces that are virtually impossible to see in the terminal, right? Sometimes even leading spaces might puzzle.

My usual go-to solution in this case is to put two boundary characters around the actual output, so that it’s delimited unambiguously:

result: «  two spaces before and three after   »

Most terminals today provide support for colors… something that I already discussed in ANSI Color. This can be used to obtain the same result but without the additional boundary characters:

# insert https://gitlab.com/polettix/notechs/-/snippets/2039857
# initializeANSI()
# { ...
result='  two before and three after   '
printf 'result: %s\n' "$boldon$whitef$purpleb$result$reset"

This gives us the following:

  two before and three after   


Of course it’s not necessary to be this generic and just rely on a couple of copy-and-pasteable variable definitions to get the same:

highlight="$(printf %b \\033)[1;97;45m" reset="$(printf %b \\033)[0m"
result='  two before and three after   '
printf 'result: %s\n' "$highlight$result$reset"

This admittedly cheap trick is easy to translate in Perl (and I guess in most of other languages!):

my $highlight = "\e[1;97;45m"; my $reset = "\e[0m";
my $result = '  two before and three after   ';
say "result: $highlight$result$reset";

I know that I err a bit too much in the copy-and-paste land… but sometimes that one line is really the only thing that’s needed!

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