在bash中回圈陣列的問題

我在 bash 中撰寫了一個非常簡單的埠掃描腳本。對于我的 ports 引數，我接受單個埠（例如：443）、逗號分隔的串列（例如：80,443）或范圍（例如：1-1000）。

當我使用單個埠或以逗號分隔的埠串列運行腳本時，一切都按預期運行：

~/projects/bash-port-scan# ./bash-port-scan.sh -i xx.xx.xxx.xxx -p 1,80,443 -v
Beginning scan of xx.xx.xxx.xxx
Port 1 closed
Port 80 open
Port 443 open
Scan complete.

~/projects/bash-port-scan# ./bash-port-scan.sh -i xx.xx.xxx.xxx -p 80 -v
Beginning scan of xx.xx.xxx.xxx
Port 80 open
Scan complete.

但是，當我使用范圍運行時，我得到：

~/projects/bash-port-scan# ./bash-port-scan.sh -i xx.xx.xxx.xxx -p 1-10 -v
Beginning scan of xx.xx.xxx.xxx
Port 1
2
3
4
5
6
7
8
9
10 closed
Scan complete.

我分配陣列的相關代碼：

portarray=()
if [[ "$ports" == *","* ]]; then
    IFS=','
    read -r -a portarray <<< $ports
    IFS=' '
elif [[ "$ports" == *"-"* ]]; then
    IFS='-' 
    read -r -a range <<< $ports
    IFS=' '
    
    first="${range[0]}"
    last="${range[1]}"
    portarray=($(seq $first 1 $last))
else
    portarray=($ports)
fi

和回圈本身：

empty=""
for p in "${portarray[@]}"; do
    result=$(nc -zvw5 $ip $p 2>&1 | grep open)
    if [ "$result" = "$empty" ]; then
        if [ $verbose -eq 1 ]; then
            str="Port "
            closed=" closed"
            echo "$str$p$closed"
        fi
    else
        str="Port "
        closed=" open"
        echo "$str$p$closed"
    fi
done

我不確定這是因為我分配埠陣列的方式，還是因為我的回圈中有問題。我對 bash 腳本比較陌生，而且我很難弄清楚我有什么問題。我在 SO 上讀到了一些命令在回圈中運行，吃掉腳本其他部分的輸出，但我不認為這里是這種情況，因為腳本確實列印到螢屏上，只是不像預期的那樣。

EDIT: Here is the full script:

#!/bin/bash

verbose=0
while [ "$1" != "" ]; do
    case "$1" in
        -h | --help )
echo "bash-port-scan.sh v0.1\r\nUsage: ./bash-port-scan.sh -i 127.0.0.1 -p 80,443\r\n./bash-port-scan.sh -i 127.0.0.1 -p 1-1000"; shift;;
        -v | --verbose )
verbose=1; shift;;
        -i | --ip ) 
ip="$2";    shift;;
        -p | --ports )
ports="$2"; shift;; 
    esac
    shift
done

if [[ $ip = "" ]]; then
    echo "Please enter an IP address with -i"
    exit
fi

if [[ $ports = "" ]]; then
    echo "Please enter the port(s) with -p"
    exit
fi

portarray=()
if [[ "$ports" == *","* ]]; then
    IFS=','
    read -r -a portarray <<< $ports
    IFS=' '
elif [[ "$ports" == *"-"* ]]; then
    IFS='-' 
    read -r -a range <<< $ports
    IFS=' '
    
    first="${range[0]}"
    last="${range[1]}"
    portarray=($(seq $first $last))
else
    portarray=($ports)
fi

if [ $verbose -eq 1 ]; then
    echo "Beginning scan of $ip"
fi

shuf -e "${portarray[@]}"

empty=""
for p in "${portarray[@]}"; do
    result=$(nc -zvw5 $ip $p 2>&1 | grep open)
    if [ "$result" = "$empty" ]; then
        if [ $verbose -eq 1 ]; then
            str="Port "
            closed=" closed"
            echo "$str$p$closed"
        fi
    else
        str="Port "
        closed=" open"
        echo "$str$p$closed"
    fi
done

echo "Scan complete."

uj5u.com熱心網友回復：

只處理portarray=(...)作業（當ports=1-10）

考慮：

$ first=1
$ last=10
$ portarray=($(seq $first 1 $last))
$ typeset -p portarray
declare -a portarray=([0]=$'1\n2\n3\n4\n5\n6\n7\n8\n9\n10')

注意：呼叫的輸出$(seq ...)被處理為帶有嵌入換行符的單個字串。

幾個想法：

### define \n as field separator; apply custom IFS in same line to limit IFS change to just the follow-on array assignment:

$ IFS=$'\n' portarray=($(seq $first 1 $last))
$ typeset -p portarray
declare -a portarray=([0]="1" [1]="2" [2]="3" [3]="4" [4]="5" [5]="6" [6]="7" [7]="8" [8]="9" [9]="10")

### use mapfile to read each *line* into a separate array entry:

$ mapfile -t portarray < <(seq $first 1 $last)
$ typeset -p portarray
declare -a portarray=([0]="1" [1]="2" [2]="3" [3]="4" [4]="5" [5]="6" [6]="7" [7]="8" [8]="9" [9]="10")

標籤：arrays linux bash for-loop

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