ksh – Unix脚本 – 需要改进性能的建议(shell脚本)

2019年7月28日 197次阅读

我有一个输入csv文件,实际上我需要在输入文件中选择第二和第三列值并需要转换两个值的时区区域(从PT到CT),一旦转换我需要替换转换后的时区值到文件.

注意：所有输入日期值都在太平洋时区,我正在转换为中央时区.

每行有5列 – 逗号分隔文件

CHID-123456323,2017-01-09 17:17:58-08:00,2017-01-09 17:39:25-08:00,hello,123456733
CHID-123456733,2017-01-09 17:16:58-08:00,2017-01-09 18:04:09-08:00,hello,123456734
CHID-123433589,2017-01-09 17:16:55-08:00,2017-01-09 17:40:29-08:00,hello,123456735
CHID-123000789,2017-01-09 17:16:52-08:00,2017-01-09 17:46:41-08:00,hello,123456736

脚本：我写了一个下面的脚本,这给出了我期待的精确结果.但是当输入记录数增加时,需要更多时间.例如2万条记录需要1小时15分钟.

任何人都可以看看这个脚本,并建议如何提高性能？

脚本：

while read i
do
    var1=`echo $i | awk -F',' '{ print $2 }'`

    var1_EPOCH=`date --date="${var1}" +%s`
    var1_CTZ=`TZ=":America/Chicago" date +"%Y-%m-%d %T" -d@$var1_EPOCH`
    sed -i "${cnt}s/${var1}/${var1_CTZ}/" filename

    var2=`echo $i | awk -F',' '{ print $3 }'`
    var2_EPOCH=`date --date="${var2}" +%s`
    var2_CTZ=`TZ=":America/Chicago" date +"%Y-%m-%d %T" -d@$var2_EPOCH`
    sed  -i "${cnt}s/${var2}/${var2_CTZ}/" filename

    cnt=$(($cnt+1))
done < filename

这是预期的输出文件

最终输出文件：

CHID-123456323,2017-01-09 19:17:58,2017-01-09 19:39:25,hello,123456733
CHID-123456733,2017-01-09 19:16:58,2017-01-09 20:04:09,hello,123456734
CHID-123433589,2017-01-09 19:16:55,2017-01-09 19:40:29,hello,123456735
CHID-123000789,2017-01-09 19:16:52,2017-01-09 19:46:41,hello,123456736

最佳答案 Ksh有足够的内置功能.

示例输入文件：

[STEP 100] $echo $BASH_VERSION
4.4.5(2)-release
[STEP 101] $cat file
CHID-123456323,2017-01-09 17:17:58-08:00,2017-01-09 17:39:25-08:00,hello,123456733
CHID-123456733,2017-01-09 17:16:58-08:00,2017-01-09 18:04:09-08:00,hello,123456734
CHID-123433589,2017-01-09 17:16:55-08:00,2017-01-09 17:40:29-08:00,hello,123456735
CHID-123000789,2017-01-09 17:16:52-08:00,2017-01-09 17:46:41-08:00,hello,123456736

剧本：

[STEP 102] $cat time.ksh
tz=America/Chicago
pattern='(.+),(.+),(.+),(.+),(.+)'
while read -r line; do
    if [[ $line =~ $pattern ]]; then
        c1=${.sh.match[1]}
        c2=${.sh.match[2]}
        c3=${.sh.match[3]}
        c4=${.sh.match[4]}
        c5=${.sh.match[5]}

        TZ=$tz printf '%(%Y-%m-%d %T)T' "$c2" | read c2
        TZ=$tz printf '%(%Y-%m-%d %T)T' "$c3" | read c3

        print -r -- "$c1,$c2,$c3,$c4,$c5"
    else
        print -r -- "$line"
    fi
done

示例输出：

[STEP 103] $ksh time.ksh < file
CHID-123456323,2017-01-09 19:17:58,2017-01-09 19:39:25,hello,123456733
CHID-123456733,2017-01-09 19:16:58,2017-01-09 20:04:09,hello,123456734
CHID-123433589,2017-01-09 19:16:55,2017-01-09 19:40:29,hello,123456735
CHID-123000789,2017-01-09 19:16:52,2017-01-09 19:46:41,hello,123456736

制作20,000行文件：

[STEP 104] $rm -f bigfile
[STEP 105] $fourlines=$(<file)
[STEP 106] $for ((i=0; i<5000; ++i)); do printf '%s\n' "$fourlines" >> bigfile; done
[STEP 107] $wc -l bigfile
   20000 bigfile

让我们对它进行性能测试：

[STEP 108] $time ksh time.ksh < bigfile > newfile

real    1m36.849s
user    0m27.376s
sys     0m46.741s
[STEP 109] $tail -n 4 newfile
CHID-123456323,2017-01-09 19:17:58,2017-01-09 19:39:25,hello,123456733
CHID-123456733,2017-01-09 19:16:58,2017-01-09 20:04:09,hello,123456734
CHID-123433589,2017-01-09 19:16:55,2017-01-09 19:40:29,hello,123456735
CHID-123000789,2017-01-09 19:16:52,2017-01-09 19:46:41,hello,123456736
[STEP 110] $ksh --version
  version         sh (AT&T Research) 93u+ 2012-08-01
[STEP 111] $
点赞