從 /etc/hosts 到對話框的 cat 特定行範圍

例如，我喜歡列出 /etc/hosts 中的所有乙太網交換機，並在對話框中顯示它們。之後，我想從列表中連接選定的交換機。

該列表應列在特定註釋行之間，例如：

/etc/主機：

... 
# ETHERNET SWITCHES
192.168.0.2 SW1
192.168.0.3 SW2
192.168.0.4 SW3
# END SWITCHES
...

以及如何使用列出的交換機名稱連接變數 $HOST 以從 /etc/hosts 與它的 IP 進行 ssh 連接？有可能是這樣的嗎？

對話框腳本：

#!/bin/bash
DIALOG_CANCEL=1
DIALOG_ESC=255
HEIGHT=0
WIDTH=0
HOST=`cat /scripts/dialog.out`
IP=`grep '$HOST' /etc/hosts | awk '{print $1}'`

display_result() {
dialog --title "$1" \
--no-collapse \
--msgbox "$result" 0 0
}
while true; do
exec 3>&1
selection=$(dialog \
--backtitle "" \
--title "MENU" \
--clear \
--cancel-label "EXIT" \
--menu "SELECT OPTION:" $HEIGHT $WIDTH 6 \
"1" "SW1" \
"2" "SW2" \
"3" "SW3" \
2>&1>/scripts/dialog.out 1>&3)
exit_status=$?
exec 3>&-
case $exit_status in
$DIALOG_CANCEL)
 clear
 exit
 ;;
$DIALOG_ESC)
 clear
 echo "Program aborted." >&2
 exit 1
 ;;
esac
case $selection in
0 )
 clear
 echo "Program terminated."
 ;;
1 )
 ssh admin@$IP
 ;;
esac
done

當使用 with 編寫腳本--menu時dialog，菜單中的第一列是一個標籤，您可以選擇是否顯示。當菜單正常時，dialog將這些標籤寫入其輸出（通常為標準錯誤，但該--stdout選項有幫助）。

如果將 IP 地址設置為標籤，則可以直接從 running 獲取地址dialog。

在手冊中，此處描述了此可選功能：

  --no-items
         Some  widgets  (checklist, inputmenu, radiolist, menu) display a
         list with two columns (a "tag" and "item", i.e., "description").
         This  option  tells  dialog  to  read shorter rows, omitting the
         "item" part of the list.  This is occasionally useful, e.g.,  if
         the tags provide enough information.

         See  also --no-tags.  If both options are given, this one is ig-
         nored.

和

  --no-tags
         Some  widgets  (checklist, inputmenu, radiolist, menu) display a
         list with two columns (a "tag" and "description").  The  tag  is
         useful  for scripting, but may not help the user.  The --no-tags
         option (from Xdialog) may be used to suppress the column of tags
         from  the  display.  Unlike the --no-items option, this does not
         affect the data which is read from the script.

         Xdialog does not  display  the  tag  column  for  the  analogous
         buildlist and treeview widgets; dialog does the same.

         Normally  dialog  allows  you  to quickly move to entries on the
         displayed list, by matching a  single  character  to  the  first
         character  of the tag.  When the --no-tags option is given, dia-
         log matches against the first character of the description.   In
         either case, the matchable character is highlighted.

您可以通過各種方式選擇行/etc/hosts，例如，使用sed：

sed -e '1,/# ETHERNET SWITCHES/d' -e '/# END SWITCHES/,9999d' /etc/hosts

你可以將它重定向到你的命令行中，方法dialog是把它放在$(and中)。

通過將快捷方式 1、2、3 與描述中的 SW1、SW2、SW3 組合併使用該--no-tags選項，您可以保持 IP 地址和描述相關聯。

您想到的範例可能是這樣的：

#!/bin/bash
INPUT=/etc/hosts
let i=0 # define counting variable
W=() # define working array
while read -r addr line; do # process file by file
 let i=$i+1
 W+=($addr "$i $line")
done < <( sed -e '1,/# ETHERNET SWITCHES/d' -e '/# END SWITCHES/,9999d' $INPUT )
FILE=$(dialog --stdout --no-tags --title "List of Switches in /etc/hosts file" --menu "Chose one" 24 80 17 "${W[@]}" ) # show dialog and store output
clear
if [ $? -eq 0 ]; then # Exit with OK
 ssh $FILE
fi

引用自：https://unix.stackexchange.com/questions/291002