创建带有访问不同目录和文件选项的脚本

Question

我一直在努力编写一个有 2 个参数的脚本，1 个要求选择年份，2 个要求选择我是否希望将最小值、最大值、平均值或全部显示为相关文件的最后一行到所选年份。

基本上，我有一个目录，其中包含不同年份（2000 年、2001 年、2002 年等）的子目录，这些目录中的子目录是几个月和几天的子目录，其中包含 (a) 个文件，告知不同的人口（虽然不是真实信息）城市作为最后一行。这是目录树的一部分：

.
|-- 2000
|   |-- 01
|   |   `-- 18
|   |       `-- ff_1177818640
|   |-- 02
|   |   |-- 02
|   |   |   `-- ff_1669027271
|   |   |-- 03
|   |   |   `-- ff_234075290
|   |   |-- 10
|   |   |   `-- ff_1584524530
|   |   |-- 14
|   |   |   `-- ff_113807345
|   |   `-- 17
|   |       `-- ff_1452228827
|   |-- 03
|   |   |-- 06
|   |   |   `-- ff_58914249
|   |   `-- 11
|   |       `-- ff_2828212321
|   |-- 04
|   |   `-- 17
|   |       `-- ff_302131884
|   |-- 06
|   |   `-- 13
|   |       `-- ff_2175615745
|   |-- 07
|   |   |-- 07
|   |   |   `-- ff_918426998
|   |   `-- 24
|   |       `-- ff_2808316425
|   |-- 08
|   |   `-- 27
|   |       `-- ff_1449825497
|   |-- 09
|   |   `-- 19
|   |       `-- ff_110255856
|   `-- 12
|       `-- 08
|           `-- ff_1621190
|-- 2001
|   |-- 03
|   |   `-- 21
|   |       `-- ff_517010375
|   |-- 05
|   |   `-- 27
|   |       `-- ff_1458621098
|   |-- 06
|   |   |-- 07
|   |   |   `-- ff_155853916
|   |   |-- 25
|   |   |   |-- ff_2382312387
|   |   |   `-- ff_270731174
|   |   `-- 29
|   |       `-- ff_3228522859
|   |-- 07
|   |   `-- 28
|   |       `-- ff_3215021752
|   |-- 09
|   |   `-- 24
|   |       `-- ff_1080314364
|   `-- 11
|       `-- 24
|           `-- ff_2313722442

所有文件的格式都相同：

2019-04-03
Wednesday
Newcastle-upon-Tyne
255362

我需要编写一个脚本来询问我需要哪一年（选择该目录），然后询问我是否希望为人口显示平均值、最小值、最大值或所有上述内容（这是文件的最后一行）。

这是我到目前为止：

#!/bin/bash

function min () {
    echo $(sort -n populations | head -1)
}

function max () {
    echo $(sort -n populations | tail -1)
}

function avg () {
    count=0
    sum=0
    while read line ; do
        num='echo ${line#* }'
        sum='expr $sum + $num'
        count='expr $count + 1'
    done < populations
    avg='expr $sum / $count'
    echo $avg
}

echo "Please enter the year: "
read s1
echo "
        Enter an option:
        1. Minimum
        2. Maximum
        3. Average
        4. All"
read s2
#echo $s2
for file in $(find ~/filesToSort/$s1 -type f) ; do
    tail -1 $file >> populations
done
echo $(cat populations)
#min
#max
#avg
rm populations

这让我选择目录，但没有给我我需要的答案，只是吐出我文件的最后几行。

Answer 1

如果我在 bash 中实现它，我会执行以下操作。我不会对此发表太多评论：尽管可以提出具体问题——如果您不知道特定命令的工作原理，请先查看 bash 手册页。

#!/bin/bash

# read the population from all the files
# map the filename to it's population figure
declare -A population
while IFS= read -d '' -r filename; do
    population["$filename"]=$(tail -1 "$filename")
done < <(find . -type f -print0)

# prompt the user for the year
read -rp "What year? " year

# find the relevant files for that year
year_files=()
for filename in "${!population[@]}"; do
    [[ $filename == ./"$year"/* ]] && year_files+=("$filename")
done
if [[ "${#year_files[@]}" -eq 0 ]]; then
    echo "No files for year '$year'"
    exit 1
fi

PS3="Select a function to calculate: "
select func in minimum maximum average quit; do
    case $func in
        minimum)
            min=${population[${year_files[0]}]}
            for file in "${year_files[@]}"; do
                if (( min > ${population[$file]} )); then
                    min=${population[$file]}
                fi
            done
            echo "Minimum for $year is $min"
            ;;
        maximum)
            max=${population[${year_files[0]}]}
            for file in "${year_files[@]}"; do
                if (( max < ${population[$file]} )); then
                    max=${population[$file]}
                fi
            done
            echo "Maximum for $year is $max"
            ;;
        average)
            count=0 sum=0
            for file in "${year_files[@]}"; do
                (( sum += ${population[$file]} ))
                (( count++ ))
            done
            echo "Average for $year is $(( sum / count ))"
            ;;
        quit) exit ;;
    esac
done

Answer 2

我写了一个简单的awk脚本，它和你正在做的一样：

# read 'year' & 'option' from user
# or you can pass as argument to the command $1<-->$year & $2<-->$option

find /path/to/$year -type f -exec \
    awk -v select=$option '
        FNR==4 { sum+=$0; avg=sum/++count; 
                 max=(max>=$0?max:$0);
                 if (count==1) min=$0;
        }
        count>1 { min=(min<=$0?min:$0);
        }
    END{ stats=min","max","avg","min"\n"max"\n"avg;
         split(stats, to_print,",");
         print to_print[select];
    }' {} +

内联说明：

# read 'year' & 'option' from user
# or you can pass as argument to the command $1<-->$year & $2<-->$option

find /path/to/$year -type f -exec \
# find all files under "/path/to/$year". $year will be substitute with the value 
# of 'year' variable read from user-input or replace it with '$1' as first argument to the command

    awk -v select=$option '
    # read the value of shell 'option' variable into an awk 'select' variable 
    # replace with '$2' as argument to the command

        FNR==4 { sum+=$0; avg=sum/++count;
        # if it's 4th line of each input file, sum-up the value into 'sum' variable
        # and calculate the 'avg' too when 'count' will increment once each 4th record in a file is read

                 max=(max>=$0?max:$0);
                 # its a Ternary operator (condition?if-true:if-false) and finding maximum value

                 if (count==1) min=$0;
                 # keep the first file's 4th line's value as minimum. you could use `NR==4` instead
        }
        count>1 { min=(min<=$0?min:$0);
        # same as max, update the 'min' if value in current file is smaller than 'min' in previous file
        }
    END{ stats=min","max","avg","min"\n"max"\n"avg;
    # saving all variables' value into single variable with comma separated. I used <min"\n"max"\n"avg> as 
    # fourth element which we will use it as "All" option that each separated with newlines.

         split(stats, to_print, ",");
         # building an array called 'to_print' from 'stats' variable above with comma separator to distinguish 
         # the elements from each other.

         print to_print[select];
         # this will print the element which user-input as an option.
         # if input 1: will print 'min'
         # if input 2: will print 'max'
         # if input 3: will print 'avg'
         # if input 4: will print 'min' \n 'max' '\n' avg
    }' {} +