input of while loop to come from output of `command`
This is sh-compatible:
tcpdump -n -r "$pcap" | while read line; do # somethingdoneHowever, sh does not have arrays, so you can't have your code like it is in sh. Others are correct in saying both bash and perl are nowadays rather widespread, and you can mostly count on their being available on non-ancient systems.
UPDATE to reflect @Dennis's comment
This works in bash:
while read line; do ARRAY[$c]="$line" c=$((c+1)) done < <(tcpdump -n -r "$pcap")
If you don't care about being bourne, you can switch to Perl:
my $pcap="somefile.pcap";my $counter = 0;open(TCPDUMP,"tcpdump -n -r $pcap|") || die "Can not open pipe: $!\n";while (<TCPDUMP>) { # At this point, $_ points to next line of output chomp; # Eat newline at the end $array[$counter++] = $_;}Or in shell, use for:
for line in $(tcpdump -n -r $pcap) do command done