remove blank lines and merge lines in shell


 
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# 1  
Old 03-08-2011
Bug remove blank lines and merge lines in shell

Hi,

I'm not a expert in shell programming, so i've come here to take help from u gurus.

I'm trying to tailor a csv file that i got to make it work for the LOAD FROM command.

I've a datatable csv of the below format -

--in file format
Code:
xx,xx,xx   ,xx , ,  , ,  ,,xx,
xxxx,, ,, xxx,
 
yyy,yy,yy, , , ,yyy,yy,
yyy,yy,,,
 
....

--our file format
Code:
xx,xx,xx   ,xx , ,  , ,  ,,xx,xxxx,, ,, xxx,
yyy,yy,yy, , , ,yyy,yy,yyy,yy,,,

As you can see above, each row of record is seperated by a line gap and also a row record is split into multiple lines. I've to make it in a format as shown below so that i can insert them into my informix db.

So i'm trying acheive two things here
1. Remove blank lines
2. Collide a data row splitted across multiple lines into one(by using the blank line as the end of a record)

Many Thanks!

Last edited by Franklin52; 03-08-2011 at 01:53 PM.. Reason: Please use code tags, thank you
# 2  
Old 03-08-2011
Code:
awk '{printf NF?$0:"\n"}'

This User Gave Thanks to yinyuemi For This Post:
# 3  
Old 03-08-2011
Try this:
Code:
awk '$1=$1' RS=  infile > outfile

# 4  
Old 03-08-2011
Quote:
Originally Posted by yinyuemi
Code:
awk '{printf NF?$0:"\n"}'

This really works good, but i cudnt exactly understand the logic behind it. I'm aware NF is for no. of fields in each line and \n is for newline.

But i cudnt understand the whole logic, if u cud explain me, that be really helpful for me to make changes to this in future.

Grateful to your comments.

Many Thanks!

---------- Post updated at 11:36 PM ---------- Previous update was at 11:31 PM ----------

Thanks for all ur comments. It works weel and good.

I just need another help here.

I need to add a extra delimiter at end of each line. I'll go with the same ex that i posted above.

-in format
xx,xx,xx ,xx , , , , ,,xx,xxxx,
xxxx,, ,, xxx,,

yyy,yy,yy, , , ,yyy,yy,,
yyy,yy,,,yyyyy,

....
# 5  
Old 03-08-2011
How about this:
Code:
awk  'BEGIN { RS="" ; FS="\n" ; OFS="," } { print $1, $2 }' < csvrec.csv > out.csv

That works by
  • Splitting records based on blank lines (RS="")
  • Using the newline as the field separator, so $1 is line 1 and $2 is line 2
  • Using "," as the output field separator, so it adds an "," between the two when you print a,b

---------- Post updated at 12:16 PM ---------- Previous update was at 12:07 PM ----------

If you need an extra "," on the end you can just do print $1, $2, ""

Last edited by Corona688; 03-08-2011 at 02:13 PM..
# 6  
Old 03-08-2011
MySQL

Quote:
Originally Posted by Corona688
How about this:
Code:
awk  'BEGIN { RS="" ; FS="\n" ; OFS="," } { print $1, $2 }' < csvrec.csv > out.csv

That works by
  • Splitting records based on blank lines (RS="")
  • Using the newline as the field separator, so $1 is line 1 and $2 is line 2
  • Using "," as the output field separator, so it adds an "," between the two when you print a,b
---------- Post updated at 12:16 PM ---------- Previous update was at 12:07 PM ----------

If you need an extra "," on the end you can just do print $1, $2, ""
It works partially good.

1. i've to implement this shell for hundreds of csv's, so i'm not quite sure on the number of lines for each record in these files. so print $1, $2 works well for two lines of record followed by a blank line. But this has to be dynamic.

2. It doesn't seem to add a extra delimiter to the end of each record, i.e before each blank line

Thanks!
# 7  
Old 03-08-2011
Good to know. How about awk 'BEGIN { RS="" ; FS="\n" } { for(N=1; N<=NF; N++) printf("%s,", $N); printf("\n"); }' < csvrec.csv then?
This User Gave Thanks to Corona688 For This Post:
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