How to improve the performance of this script?


 
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# 1  
Old 10-18-2013
How to improve the performance of this script?

Hi ,

i wrote a script to convert dates to the formate i want .it works fine but the conversion is tkaing lot of time . Can some one help me tweek this script

Code:
#!/bin/bash
file=$1
ofile=$2
cp $file $ofile
mydates=$(grep -Po '[0-9]+/[0-9]+/[0-9]+' $ofile) # gets 8/1/13
mydates=$(echo "$mydates" | sort | uniq)
for mydate in $mydates
do
   if [[ ! -z "$mydate" ]];
   then #in case there is date to process
      newdate=$(date -d"$mydate" "+%Y-%m-%d") # converts to 2013-08-01
      sed -i "s#$mydate#$newdate#g" $ofile # replaces in the text (-i option) > $formattedfile
   fi
done;

# 2  
Old 10-18-2013
You are using way too many external commands in your script which is causing it to slow down.

I would recommend using shell built-ins where ever possible to improve your script performance.

Here is an approach using ksh93 using only shell built-ins:
Code:
#!/bin/ksh93

while read line
do
        for word in $line
        do
                if [[ $word == +([0-9])\/+([0-9])\/+([0-9]) ]]
                then
                        tmp=$( printf "%(%Y-%m-%d)T" "$word" )
                        [[ -z "$str" ]] && str="$tmp" || str="$str $tmp"
                else
                        [[ -z "$str" ]] && str="$word" || str="$str $word"
                fi
        done
        printf "%s\n" "$str"
        str=""
done < file


Last edited by Yoda; 10-18-2013 at 06:35 PM.. Reason: replaced print with printf
# 3  
Old 10-18-2013
Quote:
Originally Posted by Yoda
You are using way too many external commands in your script which is causing it to slow down.

I would recommend using shell built-ins where ever possible to improve your script performance.

Here is an approach using ksh93 using only shell built-ins:
Code:
#!/bin/ksh93
 
while read line
do
        for word in $line
        do
                if [[ $word == +([0-9])\/+([0-9])\/+([0-9]) ]]
                then
                        tmp=$( printf "%(%Y-%m-%d)T" "$word" )
                        [[ -z "$str" ]] && str="$tmp" || str="$str $tmp"
                else
                        [[ -z "$str" ]] && str="$word" || str="$str $word"
                fi
        done
        printf "%s\n" "$str"
        str=""
done < file


can you provide the usage
# 4  
Old 10-18-2013
Quote:
Originally Posted by vikatakavi
can you provide the usage
Just replace file with your input file name:
Code:
done < file

# 5  
Old 10-18-2013
Quote:
Originally Posted by Yoda
Just replace file with your input file name:
Code:
done < file


i get this


UTF-8 Unicode English text, with very long lines
./edited.sh: line 17: file: ambiguous redirect
# 6  
Old 10-18-2013
Quote:
Originally Posted by vikatakavi
i get this


UTF-8 Unicode English text, with very long lines
./edited.sh: line 17: file: ambiguous redirect
That is output of file command.

Did you run a file command in your script? Post your entire script.
 
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