ref: c4629424499a36f7bf5c94ba3772bc4b631ce60e
dir: /bin/r/
#!/bin/rc
rfork e
x=1
if(! ~ $#* 0)
x=$1
awk -v 'x='^$x '
/^; /{
a[++n] = NR
} END {
cmd = a[n-x]","a[n-x+1]-1"d;"NR"d"
system("sed \''" cmd "\'' /dev/text >/tmp/a; mv /tmp/a /dev/text")
}' /dev/text