如何从包含特定字符串模式的行中提取第一个参数

如果要bash基于文件内容生成变量，请尝试以下操作：

# read the file and extract information line by line
declare -A hash                     # delcare hash as an associative array
while IFS= read -r line; do
    key="${line#*~}"                # convert "1~auth_flag~" to "auth_flag~"
    key="${key%~*}_ids"             # convert "auth_flag~" to "auth_flag_ids"
    hash[$key]+="${line%%~*},"      # append the value to the hash
done < "mail_status.txt"

# iterate over the hash to create variables
for r in "${!hash[@]}"; do          # r is assigned to "auth_flag_ids", "download_flag_ids" and "copy_flag_ids" in tern
    printf -v "$r" "%s" "${hash[$r]%,}"  # create a variable named "$r" and assign it to the hash value by trimming the trailing comma off
done

# check the result
printf "%s=\"%s\"\n" "auth_flag_ids" "$auth_flag_ids"
printf "%s=\"%s\"\n" "download_flag_ids" "$download_flag_ids"
printf "%s=\"%s\"\n" "copy_flag_ids" "$copy_flag_ids"

首先，它读取文件的各行，并逐行提取变量名称和值。它们存储在关联数组中hash。 接下来，迭代键的hash名称以创建名称为“ auth_flag_ids”，“ download_flag_ids”和“ copy_flag_ids”的变量。 printf -v var创建一个变量var。该机制对于引起对变量的间接引用很有用。