使用bash处理大量数据

Question

我必须使用bash脚本处理文件夹中的大量txt文件.每个文件包含数百万行,它们的格式如下:

档案#1:

en ample_1 200
it example_3 24
ar example_5 500
fr.b example_4 570
fr.c example_2 39
en.n bample_6 10

档案#2:

de example_3 4
uk.n example_5 50
de.n example_4 70
uk example_2 9
en ample_1 79
en.n bample_6 1

...

我必须通过"en"或"en.n"进行过滤,在第二列中找到重复的出现次数,求和第三列并得到如下的排序文件:

en ample_1 279
en.n bample_6 11

我的脚本在这里:

#! /bin/bash
clear
BASEPATH=<base_path>
FILES=<folder_with_files>
TEMP_UNZIPPED="tmp"
FINAL_RES="pg-1"
#iterate each file in folder and apply grep
INDEX=0
DATE=$(date "+DATE: %d/%m/%y - TIME: %H:%M:%S")
echo "$DATE" > log
for i in ${BASEPATH}${FILES}
do
FILENAME="${i%.*}"
if [ $INDEX = 0 ]; then
  VAR=$(gunzip $i)
  #-e -> multiple condition; -w exact word; -r grep recursively; -h remove file path
  FILTER_EN=$(grep -e '^en.n\|^en ' $FILENAME > $FINAL_RES)
  INDEX=1
  #remove file to free space
  rm $FILENAME
else
  VAR=$(gunzip $i)
  FILTER_EN=$(grep -e '^en.n\|^en ' $FILENAME > $TEMP_UNZIPPED)
  cat $TEMP_UNZIPPED >> $FINAL_RES
  #AWK BLOCK
  #create array a indexed with page title and adding frequency parameter as value.
  #eg. a['ciao']=2 -> the second time I find "ciao", I sum previous value 2 with the new. This is why i use "+=" operator
  #for each element in array I print i=page_title and array content such as frequency
  PARSING=$(awk '{  page_title=$1" "$2;
                    frequency=$3;
                    array[page_title]+=frequency
                  }END{
                    for (i in array){
                      print i,array[i] | "sort -k2,2"
                    }
                  }' $FINAL_RES)

  echo "$PARSING" > $FINAL_RES
  #END AWK BLOCK
  rm $FILENAME
  rm $TEMP_UNZIPPED
fi
done
mv $FINAL_RES $BASEPATH/06/01/
DATE=$(date "+DATE: %d/%m/%y - TIME: %H:%M:%S")
echo "$DATE" >> log

一切正常,但执行需要很长时间.有没有人知道如何获得相同的结果,更少的时间和更少的代码行？

Answer 1

UNIX shell是一个操作文件和进程以及对工具进行调用的环境.shell调用操作文本的UNIX工具是awk所以只需使用它:

$ awk '$1~/^en(\.n)?$/{tot[$1" "$2]+=$3} END{for (key in tot) print key, tot[key]}' file | sort
en ample_1 279
en.n bample_6 11

你的脚本有很多问题要评论,这表明你是shell编程的初学者 - 获得由Chris Johnson撰写的Bash Shell Scripting Recipes和Arnold Robins的Effective Awk Programming,第4版.