Bash - if 语句中的错误代码不起作用

Question

我正在编写一个 bash 脚本，它会备份到已安装的驱动器。

备份本身可以正常工作，但是即使在传输过程中出现错误，它也会说成功。

backup() {
echo -e "Backup Started\n" >> $1
echo -e "Mounting backup Drive" >> $1
mount $2 /mnt 2>>$1
if [ $? -eq 0 ] ; then
   echo -e "Backup Drive: $2 mounted successfully" >> $1
   cd /
   echo -e "Sync data to $2\n" >> $1
   nice -n 19 rsync -lHa --exclude-from '/opt/ts/bin/exclude.txt' / /mnt/ 2> ${ERROR}
   local RETURNCODE=$?
   if [ $RETURNCODE -eq 23 ] ; then backup_failed "Backup Warning: Some files did not copy" $1 $2; fi
   if [ $RETURNCODE -eq 20 ] ; then backup_failed "Backup Failed: Transfer was terminated prematurely" $1 $2; fi
   if [ $RETURNCODE -eq 11 ] ; then backup_failed "Backup Failed: Input/Output Error [URGENT]" $1 $2; fi
   if [ $RETURNCODE -ne 0 ] ; then backup_failed "Backup Failed: Error while copying data" $1 $2; fi
   echo -e "Backup completed Successfully with code $RETURNCODE `date`\n" >> $1
   echo -e >> $1
   printf "Time taken: "%dh:%dm:%ds"\n" $(($SECONDS/3600)) $(($SECONDS%3600/60)) $(($SECONDS%60)) >> $1
   echo -e "##############################\n" >> $1
   mkdir -p /mnt/mnt /mnt/proc /mnt/tmp /mnt/lost+found
   cp -a /proc/mounts /proc/filesystems /mnt/proc
   umount $2
fi
}

尽管 $RETURNCODE 给出的值为 20，但它不会触发。输出如下。

安装备份驱动器 备份驱动器：/dev/hda4 挂载成功 同步数据到 /dev/hda4

备份成功完成，代码 20 Sun May 4 11:04:48 EST 2014

耗时：0h:0m:3s

#

如果有人有任何建议，将不胜感激:)

Answer 1

您确定函数 backup_failed 的行为符合预期吗？

另请注意，当 RETURNCODE 不为 0 且 backup_failed 不会终止脚本时，会触发两次 backup_failed：

if [ $RETURNCODE -eq 20 ] ; then backup_failed ...
...
if [ $RETURNCODE -ne 0 ] ; then backup_failed ...

希望这会有所帮助。