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bsleep - Breakable Sleep
========================
bsleep is a sleep that breaks as soon as you press 'b'.
It makes clever use of the -t (timeout) and -n (read n bytes) parameters
of the bash built-in: read.
bsleep can be used to quickly test something and chain a quick undo
command right after you initial command.
example usage:
echo "do something"; bsleep; echo "quickly undo"
The other day I was tinkering with an iptables ruleset and needed exactly
that. So quickly hacked it quick'n'dirty (originally as a one-liner).
The Bash-Shellfunction:
function bsleep () {
local c=1;
local INPUT;
while [ ! "$INPUT" == "b" ]; do
printf "$c "; # comment out if you prefer silent
c=$(($c+1));
read -s -n1 -t1 INPUT;
done;
printf "\n";
}
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P.S.:
In general I strife to get rid of bashisms in my daily doing. I noticed
that the built-in read functions of some POSIX shells (e.g. like ksh) do
not provide -t or -n.
So I aim to write a little bsleep-program in C in the future.
Update:
DIR 2024-06-30 - bsleep (rewritten in C)