Stephane Chazelas wrote in
<20230902084912.vdfedsgbnat2w...@chazelas.org>:
|2023-09-01 23:28:50 +0200, Steffen Nurpmeso via austin-group-l at The \
|Open Group:
...
|>|FWIW, a "printf %b" github shell code search returns ~ 29k
|>|entries
|>|(https://github.com/search?q=printf+%25b+language%3AShell&type=code&l=Sh\
|>|ell)
...
|> Actually this returns a huge amount of false positives where
|> printf(1) and %b are not on the same line, let alone the same
...
|Apparently, we can also search with regexps and searching for
|printf.*%b
|(https://github.com/search?q=%2Fprintf.*%25b%2F+language%3AShell&type=code)
|It's probably a lot more accurate. It returns ~ 19k.
...
|> Furthermore it shows a huge amount of false use cases like
...
|Yes, I also see a lot of echo -e stuff that should have been
|echo -E stuff (or echo alone in those (many) implementations
|that don't expand by default or use the more reliable printf
|with %s (not %b)).
|
|> It seems people think you need this to get colours mostly, which
...
|Incidentally, ANSI terminal colour escape sequences are somewhat
|connecting those two %b's as they are RGB (well BGR) in binary
|(white is 7 = 0b111, red 0b001, green 0b010, blue 0b100), with:
|
|R=0 G=1 B=1
|printf '%bcyan%b\n' "\033[3$(( 2#$B$G$R ))m" '\033[m'
|
|(with Korn-like shells, also $(( 0b$B$G$R )) in zsh though zsh
|has builtin colour output support including RGB-based).
..and, off-topic, but in my opinion that is also false usage, one
should use tput(1) instead, and then simply printf(1) (or echo(1)
(or cat(1))) the output, something like, fwiw :),
color_init() {
[ -n "${NO_COLOUR}" ] && return
# We do not want color for "make test > .LOG"!
if [ -t 1 ] && command -v tput >/dev/null 2>&1; then
{ sgr0=$(tput sgr0); } 2>/dev/null
[ $? -eq 0 ] || return
{ saf1=$(tput setaf 1); } 2>/dev/null
[ $? -eq 0 ] || return
{ saf2=$(tput setaf 2); } 2>/dev/null
[ $? -eq 0 ] || return
{ saf3=$(tput setaf 3); } 2>/dev/null
[ $? -eq 0 ] || return
{ saf5=$(tput setaf 5); } 2>/dev/null
[ $? -eq 0 ] || return
{ b=$(tput bold); } 2>/dev/null
[ $? -eq 0 ] || return
COLOR_ERR_ON=${saf1}${b} COLOR_ERR_OFF=${sgr0}
COLOR_DBGERR_ON=${saf5} COLOR_DBGERR_OFF=${sgr0}
COLOR_WARN_ON=${saf3}${b} COLOR_WARN_OFF=${sgr0}
COLOR_OK_ON=${saf2} COLOR_OK_OFF=${sgr0}
unset saf1 saf2 saf3 b
fi
}
...
printf '%s%s%s' "${COLOR_WARN_ON}" "$SOME_MSG" "${COLOR_WARN_OFF}"
Of course this is also only ANSI via sgr0 (:-|
|Speaking of stackexchange, on the June data dump of
|unix.stackexchange.com:
|
|stackexchange/unix.stackexchange.com$ xml2 < Posts.xml | grep -c 'printf\
|.*%b'
|494
|
|(FWIW)
|
|Compared with %d (though that will have entries for printf(3) as well):
|
|stackexchange/unix.stackexchange.com$ xml2 < Posts.xml | grep -c 'printf\
|.*%d'
|3444
I am totally stunned by the ratio. I myself have never used %b
(like this, aka for printf).
--End of <20230902084912.vdfedsgbnat2w...@chazelas.org>
--steffen
|
|Der Kragenbaer, The moon bear,
|der holt sich munter he cheerfully and one by one
|einen nach dem anderen runter wa.ks himself off
|(By Robert Gernhardt)
