while循环的输入来自`command`的输出

Question

#I used to have this, but I don't want to write to the disk
#
pcap="somefile.pcap"
tcpdump -n -r $pcap > all.txt
while read line; do  
  ARRAY[$c]="$line"
  c=$((c+1))  
done < all.txt  

以下无法正常工作.

# I would prefer something like...
#
pcap="somefile.pcap"
while read line; do  
  ARRAY[$c]="$line"
  c=$((c+1))  
done < $( tcpdump -n -r "$pcap" )

在谷歌搜索结果太少(不明白,我想找到:(什么的).我想保持它Bourne兼容(/ bin/sh的),但它并不具备如此.

Answer 1

这是sh兼容的:

tcpdump -n -r "$pcap" | while read line; do  
  # something
done

但是,sh没有数组,所以你不能拥有像它一样的代码sh.别人都在说正确的都bash和perl是时下相当普遍的,你可以在他们是可用非古系统大都数.

更新以反映@Dennis的评论

Answer 2

这适用于bash:

while read line; do  
  ARRAY[$c]="$line"
  c=$((c+1))  
done < <(tcpdump -n -r "$pcap")