用bash中的循环生成命令参数

Question

是否可以在代码中放置循环？想要为当前的每一天绘制一个区域并保存到文件中。一种方法是硬编码，但这并不好玩，并且由于每个月的天数不切实际。希望把像一个"for each day of mont ..."或类似"while day < lastDay ...."

#!/bin/bash 
    # genererar stapeldiagram för nuvarade månad 
    # sparar fil enl. YYYY-MM-bar.png 
    # använd tex. crontab 1min. 
    # om script körs manuellt, sudo 

    #TODO: argument för specefik månad enl. "$ simple_bar_generator.sh YYYY-MM" 

    month=$(date +%m) 
    day=$(date +%d) 
    monthStr=$(date -d "-$(date +%d) days +1 month" +%B) 
    year=$(date +%Y) 
    firstDay=$(date -d "-0 month -$(($(date +%d)-1)) days" +%Y%m%d)  #YYYY-MM-DD 
    lastDay=$(date -d "$firstDay + 1 month - 1 day" +%Y%m%d)    #YYYY-MM-DD 

    source /etc/elmatare.conf 
    imgPath="/var/www/img/" 
    tempPath="/tmp/$year-$month-bar.png" 
    /usr/bin/rrdtool graph $tempPath \ 
     --start $firstDay \ 
     --end $lastDay \ 
     --width 1600 \ 
     --height 400 \ 
     --title 'Förbrukning $monthStr Högmora 4:4' \ 
     --vertical-label 'kWh' \ 
     --alt-y-grid \ 
     --right-axis 1:0 \ 
     --units-exponent 2 \ 
     --color GRID#00000050 \ 
     --color MGRID#00000080 \ 
    while [ $firstDay -le $lastDay ]; do 
     DEF:tot=$powerDBPath:Tot:AVERAGE:start=YYYYMMDD:end=YYYYMMDD \ 
     CDEF:w=tot,3600,* \ 
     CDEF:energiK=tot,1000,/ \ 
     VDEF:value_sum=energiK,TOTAL \ 
     CDEF:value_area=w,w,-,value_sum,+ \ 
     AREA:value_area#AAAAee \ 
     LINE1:value_area1#000000 \ 
     GPRINT:value_sum:"For testing purposes $day: %0.2lfkWh" \ 
    done 
    mv $tempPath $imgPath 

没有运气！

$ ./simple_bar_generator.sh 
./simple_bar_generator.sh: line 31: syntax error near unexpected token `do' 
./simple_bar_generator.sh: line 31: `while [ $firstDay -le $lastDay ]; do' 

最终循环看起来像：为变量添加索引，rrdtool不接受变量的重用。

args=() 
day=$firstDay 
i=1 
while [[ $day != $(date -d "$lastDay + 1 days" +%Y%m%d) ]]; do  
    dayStop=$(date -d "$day + 1 days" +%Y%m%d) 
    args+=(
    DEF:tot$i="$powerDBPath:$DS:AVERAGE:start=$day:end=$dayStop" 
    CDEF:w$i=tot$i,3600,"*" 
    CDEF:energiK$i=tot$i,1000,/ 
    VDEF:value_sum$i=energiK$i,TOTAL 
    CDEF:value_area$i=w$i,w$i,-,value_sum$i,+ 
    AREA:value_area$i#AAAAee 
    LINE1:value_area$i#000000 
    GPRINT:value_sum$i:"Förbrukning (för testning) $day %0.2lfkWh\n" 
) 
day=$(date -d "$day + 1 days" +%Y%m%d) 
i=$[$i+1] 
done 

Answer 1

生成的参数列表事前，就像这样：

args=() 
day=$firstDay 
while [[ $day <= $lastDay ]]; do 
    args+=(
    DEF:tot="$powerDBPath:Tot:AVERAGE:start=YYYYMMDD:end=YYYYMMDD" 
    CDEF:w=tot,3600,"*" 
    CDEF:energiK=tot,1000, 
    VDEF:value_sum=energiK,TOTAL 
    CDEF:value_area=w,w,-,value_sum,+ 
    "AREA:value_area#AAAAee" 
    "LINE1:value_area1#000000" 
    GPRINT:value_sum:"For testing purposes $day: %0.2lfkWh" 
) 
day=$(date -d "$day + 1 days" +%Y%m%d) 
done 

...然后，后循环完成，运行命令扩展它产生的阵列：

rrdtool static-args-here "${args[@]}"