我正在尝试在shell脚本中编写代码。当我尝试将代码从批处理脚本转换为外壳脚本时，出现错误。

批处理文件代码

:: Create a file with all latest snapshots
FOR /F "tokens=5" %%a in (' ec2-describe-snapshots ^|find "SNAPSHOT" ^|sort /+64') do set "var=%%a" 
set "latestdate=%var:~0,10%" 
call ec2-describe-snapshots |find "SNAPSHOT"|sort /+64 |find "%latestdate%">"%EC2_HOME%\Working\SnapshotsLatest_%date-today%.txt"

外壳脚本中的代码

#Create a file with all latest snapshots
FOR snapshot_date in $(' ec2-describe-snapshots | grep -i "SNAPSHOT" |sort /+64') do set "var=$snapshot_date" 
set "latestdate=$var:~0,10" 
ec2-describe-snapshots |grep -i "SNAPSHOT" |sort /+64 | grep "$latestdate">"$EC2_HOME%/SnapshotsLatest_$today_date"

我想根据日期对快照进行排序，并将最新日期创建的快照保存在文件中。

ece-describe-snapshots的样本输出：

`SNAPSHOT        snap-5e20   vol-f660    completed       2013-12-10T08:00:30+0000        100%    109030037527    10      2013-12-10: Daily Backup for i-2111 (VolID:vol-f9a0 InstID:i-2601)`

它将包含这样的记录

snaphsot的最新文件应包含：

SNAPSHOT    snap-cdd617f3   vol-f66409a0    completed   2013-12-04T09:24:50+0000    100%    109030037527    10  2013-12-04: Daily Backup for Sanjay_Test_Machine (VolID:vol-f66409a0 InstID:i-26048111)
SNAPSHOT    snap-c7d617f9   vol-3d335f6b    completed   2013-12-04T09:24:54+0000    100%    109030037527    10  2013-12-04: Daily Backup for sachin_test_VPC (VolID:vol-3d335f6b InstID:i-e1c443d6)

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