代码示例如下图所示,在while中变量namelist、image_hash无法传到循环外部。
原因:使用了管道的缘故,当启用管道时,会生成一个subshell,while循环的代码在subshell中执行
function generate_ota_package()
{
local namelist=$filelist" "$ota_hash_sig
openssl sha -sha256 $filelist | awk '{print $2}' | head -c 64 > $filelist_hash
reinit_file $filelist_hash
cat $filelist | while read line
do
partition_name=`echo $line | awk '{print $1}'`
image=`echo $line | awk '{print $2}'`
if [[ $image == "" ]];then
continue
fi
namelist=$namelist" "$image
echo "============"$namelist
image_hash=`openssl sha -sha256 $image | awk '{print $2}'`
echo $partition_name" "$image" "$image_hash >> $filelist_hash
done < $filelist
echo $namelist
echo $image_hash
signature_ota
tar cvzf $ota_name $namelist
}
修改方案如下:
function generate_ota_package()
{
local namelist=$filelist" "$ota_hash_sig
openssl sha -sha256 $filelist | awk '{print $2}' | head -c 64 > $filelist_hash
reinit_file $filelist_hash
while read line
do
partition_name=`echo $line | awk '{print $1}'`
image=`echo $line | awk '{print $2}'`
if [[ $image == "" ]];then
continue
fi
namelist=$namelist" "$image
echo "============"$namelist
image_hash=`openssl sha -sha256 $image | awk '{print $2}'`
echo $partition_name" "$image" "$image_hash >> $filelist_hash
done < $filelist
echo $namelist
echo $image_hash
signature_ota
tar cvzf $ota_name $namelist
}