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使用 for、while 行為讀取文件

tag-icon • tag-icon bash shell-script cat for shell-builtin
使用 for、while 行為讀取文件

考慮以下場景

2 個虛擬機器 - 192.168.229.131、192.168.229.132

/etc/hosts兩個虛擬機器的檔案中的 IP 均為 192.168.229.151 和 192.168.229.152

假設有大約 50 個虛擬機，就像我上面所說的。但到目前為止，我只考慮以上2個。

我將 2 個虛擬機器的 ip 儲存在名為 server 的檔案中

#cat server
192.168.229.131
192.168.229.132

下面是腳本

#!/bin/bash
cat server | while read line
do
/usr/bin/sshpass -e ssh -t -q -o StrictHostKeyChecking=no root@$line << EOF
echo successfully logged in $line
MYIP=$(ifconfig | sed -En 's/127.0.0.1//;s/.*inet (addr:)?(([0-9]*\.){3}[0-9]*).*/\2/p')
for i in 151 152
do
echo 192.168.229.\$i >> errips
done
for data in `cat errips`
do
echo data currently has $data
grep $data /etc/hosts
if [ $? -eq 0 ]
then
sed -i "s/$data/$MYIP/g" /etc/hosts
echo "completed"
unset MYIP
rm -rf errips
exit 0
fi
done
EOF
done

下面是輸出

root@master:~# ./script
cat: errips: No such file or directory
successfully logged in 192.168.229.131
cat: errips: No such file or directory
successfully logged in 192.168.229.132

為什麼登入伺服器後的for循環會在登入之前執行？

我嘗試使用下面的內容而不是“for”

cat errips |while read line
echo line currently has $line

在這種情況下，我發現該行仍在本地主機中的伺服器檔案中獲取IP，而它應該從我遠端登入的伺服器的errips檔案中讀取它。

輸出為

line currently has 192.168.229.131
line currently has 192.168.229.132

而我期望它應該讀取文件“errips”中的值並且輸出應該如下所示

line currently has 192.168.229.151
line currently has 192.168.229.151

現在，我嘗試了以下命令

cat errips |while read data
echo data currently has $data

在這種情況下，值資料的輸出為空

data currently has 
data currently has

我如何逐行讀取遠端伺服器中的檔案“errips”，並 grep 查找 /etc/hosts 中的行，然後執行 if 循環，這將用正確的 ip 替換錯誤的 ip？

答案1

您需要單引號您的此處文件限製字串，否則將啟用參數替換。這應該有效：

#!/bin/bash
cat server | while read line
do
  /usr/bin/sshpass -e ssh -t -q -o StrictHostKeyChecking=no root@$line <<'EOF'
  echo successfully logged in $line
  MYIP=$(ifconfig | sed -En 's/127.0.0.1//;s/.*inet (addr:)?(([0-9]*\.){3}[0-9]*).*/\2/p')
  for i in 151 152
  do
    echo 192.168.229.$i >> errips
  done
  for data in `cat errips`
  do
    echo data currently has $data
    grep $data /etc/hosts
    if [ $? -eq 0 ]
    then
      sed -i "s/$data/$MYIP/g" /etc/hosts
      echo "completed"
      unset MYIP
      rm -rf errips
      exit 0
    fi
  done
EOF
done

請注意 EOF 周圍的單引號。為了進一步闡明，請嘗試以下操作：

/usr/bin/sshpass -e ssh -t -q -o StrictHostKeyChecking=no root@<your_ip> 'k=1; echo $k'
/usr/bin/sshpass -e ssh -t -q -o StrictHostKeyChecking=no root@<your_ip> "k=1; echo $k"
/usr/bin/sshpass -e ssh -t -q -o StrictHostKeyChecking=no root@<your_ip> "k=1; echo \$k"

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