錯誤在bash處理/ expect腳本

Question

粘貼下面是一個bash腳本，結合期望代碼，其中：

• 通過ssh連接到遠程主機，收集文件並準備TGZ文件;
• 將tgz文件從遠程主機複製到本地機器;
• 再次通過ssh連接到遠程主機並刪除以前創建的tgz文件;
• 最後，在本地機器上提取tgz文件。

一切正常，如果傳遞的參數是有效的（即$host，$user和$pass）。如果其中一個不正確，腳本會掛起。我想知道如果在用戶名（或密碼）不正確的情況下如何包含一些錯誤處理（例如，在$ cmd1中）來終止帶有消息的腳本？

在此先感謝任何指針。

#!/bin/bash 
prog=$(basename $0) 
NO_ARGS=0 
E_OPTERROR=85 

# Script invoked with no command-line args? 
if [ $# -eq "$NO_ARGS" ]; then 
    echo "Usage: $prog [-h host] [-u username] [-p password]" 
    echo "  $prog -help for help." 
    exit $E_OPTERROR 
fi 

showhelp() { 
    echo "Usage: $prog [-h host] [-u username] [-p password]" 
    echo " -h: host" 
    echo " -u: username" 
    echo " -p: password" 
    echo " -help: this help message" 
    exit 2 
} 

user="" 
host="" 
pass="" 
now=$(date +"%m-%d-%Y") 
dir="data_$now" 
file="data.tgz" 

while getopts "h:u:p:help" name; do 
    case $name in 
    h) 
     host=$OPTARG 
    ;; 
    u) 
     user=$OPTARG 
    ;; 
    p) 
     pass=$OPTARG 
    ;; 
    help) 
     showhelp $0 
    ;; 
    esac 
done 

if [ -d "$dir" ]; then 
    rm -R $dir 
    mkdir $dir 
else 
    mkdir $dir 
fi 

cmd1=$(expect << EOF 
spawn ssh $user@$host 
expect "password: " 
send "$pass\n" 
expect "$ " 
send "cd /tmp\n" 
expect "$ " 
send "tar -czf $file \`find . -maxdepth 1 -name 'f2p_*' -print\`\n" 
expect "$ " 
send "logout" 
EOF) 

cmd2=$(expect << EOF 
spawn scp $user@$host:/tmp/$file $dir 
expect "password: " 
send "$pass\n" 
expect "$ " 
EOF) 

CMD3=$(expect << EOF 
spawn ssh $user@$host 
expect "password: " 
send "$pass\n" 
expect "$ " 
send "cd /tmp\n" 
expect "$ " 
send "rm $file\n" 
expect "$ " 
send "logout" 
EOF) 

echo "$cmd1" 
echo "$cmd2" 
echo "$cmd3" 
cd $dir 
tar -xzf $file 
rm $file 
count=$(ls -1 | wc -l | awk '{gsub(/^ +| +$/, "")}1') 
cd .. 
#clear 
echo "All done. Extracted $count *.net files." 

Answer 1

的expect命令可以基於不同的答案不同的動作。

例如，你可以定義$ CMD1這樣的：

cmd1=$(expect << EOF 
spawn ssh $user@$host 
expect "password: " 
send "$pass\n" 
expect { 
{ 
    "Permission denied, please try again." { 
     send_user "Wrong password" 
     exit 
    } 
    "$ " { 
     send "cd /tmp\n" 
     expect "$ " 
     send "tar -czf $file \`find . -maxdepth 1 -name 'f2p_*' -print\`\n" 
     expect "$ " 
     send "logout" 
    } 
} 
EOF) 

如果提供的密碼不能正常工作，該腳本將退出並打印消息「密碼錯誤」。

對於更高級的用法，請看看手冊頁。這裏有幾個例子和許多其他選項。

Answer 2

expect { 
{ 
    "Permission denied, please try again." { 
     send_user "Wrong password" 
     } 
    "$ " { 
     send "cd /tmp\n" 
     expect "$ " 
     send "tar -czf $file \`find . -maxdepth 1 -name 'f2p_*' -print\`\n" 
     expect "$ " 
     send "logout" 
    } 

在這裏，當我們刪除命令退出，預計應打印「密碼錯誤」，比通過發送做下一部分「CD/tmp目錄\ n」 ....... 是不是正確？