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Array 陣列

Learning
SamplesList Array
  • 陣列長度：${#str_list[@]}
  • 陣列內容：${str_list[@]} 或 ${str_list[*]}
#!/bin/bash
str_list=("aaa" "bbb" "ccc" "ddd")
echo ${#str_list[@]}
for i in ${str_list[@]}
do
  echo "$i"
done
# Script to split a string based on the delimiter
my_string="Ubuntu;Linux Mint;Debian;Arch;Fedora"
IFS=';' read -ra my_array <<< "$my_string"

#Print the split string
for i in "${my_array[@]}"
do
    echo $i
done
# Script to split a string based on the delimiter
my_string="Ubuntu;Linux Mint;Debian;Arch;Fedora"  
my_array=($(echo $my_string | tr ";" "\n"))

#Print the split string
for i in "${my_array[@]}"
do
    echo $i
done
local n=0

until [[ $n -eq ${#asr_array[@]} ]]; do
    asr=${asr_array[$n]}
    echo $asr
    let n++
done

用 printf 輸出陣列內容，搭配 grep 可做條件判斷式

# --- Ban active IPs not already banned ---
for ip in $active_ips; do
  if ! printf '%s\n' "${banned_ips[@]}" | grep -qw "$ip"; then
    log "Banning IP via Fail2Ban: $ip"
    fail2ban-client set "$JAIL" banip "$ip"
  fi
done

 

移除陣列內容
# Delete the 3th element of the array
unset str_list[3]
String to Array
while read c1 c2 c3 c4 c5 c6;do
    day="$c1"
    ncalls="$c4"
    scalls="$c6"
    asr=$(echo "scale=2; $scalls * 100 / $ncalls" | bc)
    day_str+="$day "
    asr_str+="$asr "
    calls_str+="$ncalls "
done < $tmpfile

read -ra day_array <<< "$day_str"
read -ra asr_array <<< "$asr_str"
read -ra calls_array <<< "$calls_str"
mapfile

將檔案內容或指令輸出，逐行寫入陣列。

基本用法

  • 以下 lines 是陣列資料
  • mapfile lines < file.txt
  • mapfile -t lines < <(command)
# File
mapfile MYFILE < example.txt
echo ${MYFILE[@]}
echo ${MYFILE[0]}

# Command
mapfile -t GEEKSFORGEEKS < <(printf "Item 1\nItem 2\nItem 3\n")
echo  ${GEEKSFORGEEKS[@]}

範例：檢查 ufw 的阻擋 IP

# --- Remove UFW rules for inactive IPs ---
for ip in $inactive_ips; do
  # Get UFW rules for this IP in reverse order to avoid shifting rule numbers on deletion
  mapfile -t rules < <(ufw status numbered | grep "$ip" | grep "DENY IN" | tac)
  for rule in "${rules[@]}"; do
    rule_number=$(echo "$rule" | awk -F'[][]' '{print $2}')
    log "Removing UFW rule #$rule_number for IP: $ip"
    ufw --force delete "$rule_number"
  done
done

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