Shell Programming and Scripting

Hi ,

Could someone please help me for following script:

Code:

perl -pi -e 's/\"//g' ${FILELIKE}*.csv
perl -pi -e '$_ ="" if ($.==1);' ${FILELIKE}*.csv

What these 2 commands are doing?

Thanks,
Preetpal

Moderator's Comments:

How to use code tags

Code:

 
 
#Replace all the "(double quotes) to none in all csv files
 
perl -pi -e 's/\"//g' ${FILELIKE}*.csv
 
# delete the first line in all the csv files.
perl -pi -e '$_ ="" if ($.==1);' ${FILELIKE}*.csv

Sorry to ask you these questions but i am a beginner in this.

1.what does -pi and -e stands for?
2. What does 's/\"//g' stands for?
3.What does '$_ ="" if ($.==1);' stands for?

1) -p is print all lines by default.
-i is inplace editing of file. So whatever changes you make would be written in file. A safer way is to use "-i.bak" as in perl -pi.bak -e .... so that you have a backup of the original file.

2) s/\"//g --> All instances of double-quotes are deleted (or rather substituted with null)

3) $_ ="" if ($.==1) --> $. refers to line number. If first line is being read, then replace the contents of first line with nothing.

4) And please learn how to use code tags.

Thanks a lot balajesuri