On 2020-11-08 21:41:51 +0000, Harald van Dijk wrote:
>
> There are two good workarounds. One is yours, which ensures read a b is not
> executed in a subshell environment. Depending on the use case, another good
> alternative is
>
> echo 12 34 | {
> read a b
> echo "'${a}''${b}'"
> }
>
> This still executes `read a b` in a subshell environment, but lets the
> following commands that use $a and $b also execute in that same subshell
> environment. This workaround can be used when the following commands do not
> need to read from the original stdin.
If the original stdin is needed, exec can be used. As in (the echo 1 2 is
supposed to simulate "the original stdin"):
echo 1 2 | {
exec 3<&0
echo 3 4 | {
read a b
printf '%s %s\n' "$a" "$b"
read a b <&3
printf '%s %s\n' "$a" "$b"
}
}
But yes, this has the potential to get bit confusing fairly quickly.
Have a nice day,
W.
--
There are only two hard things in Computer Science:
cache invalidation, naming things and off-by-one errors.
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