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Grepping text block by block by using for loop

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# 8  
Old 09-24-2012
Quote:
Originally Posted by RudiC
It will not be too performant on large files, as awk always scans through the entire file!
Code:
for ((i=1;i<=5;i++))
do
echo Block: $i
awk     '/^Hi welcome/ {++fn}
     {if (fn==blockno) print}
    ' blockno=$i test
done

Hi Rudic,

Using for loop it will take too much of time and every time awk reads file from start. instead of using for loop we can use awk directlly.

try this..
Code:
awk '{if($0 ~ /^Hi welcome/){a++; s=$0}else{if($0 !~ /Bye\*\*/){if(s != "") { s=s"\n"$0}}else{s=s"\n"$0; print "Block : "a"\n"s"\n"}}}' file

another approach..

Code:
awk '{if($0 ~ /Bye\*\*/){a++;s=s"\n"$0;print "Block : "a"\n"s"\n";s=""}else{if(s){s=s"\n"$0}else{s=$0}}}' file

# 9  
Old 09-24-2012
If you don't have any escape sequence in "blah blah blah", try this (made in bash):
Code:
par=""
while IFS= read line; do
par="${par}${line}\n"
if [ "$line" = "Bye**" ]; then
 par=${par%\\n}
 echo -e "${par}" >tmpfile
 cat tmpfile # or do whatever you like with it
 par=""
fi
done <inputfile

--
Bye
# 10  
Old 09-24-2012
Dear RudiC,

Sorry, it may sound foolish but may I know where to enter input file name and what will be output file name? Also, wondering where is "Bye**" pattern is placed in the script.
# 11  
Old 09-24-2012
Sorry, the input filename I used is "test" - pls replace. The ouput is sent to stdout, you can use the redirection ">" to send it to e.g. "tempfile" or whatever filename you like. We dont need the "Bye**" pattern if the input file is structured like you posted: "Bye**" immediately followed by the next "Hi welcome".
# 12  
Old 09-24-2012
Wow Len RudiC and Pamu,

Thanks for your efforts and prompt help which was badly needed.
Special thanks to Len, it worked exactly how I wanted it to work.

Thank you once again.
God bless you all
Take care
Anu.
# 13  
Old 09-24-2012
Quote:
Originally Posted by pamu
Hi Rudic,

Using for loop it will take too much of time and every time awk reads file from start.

@pamu: I recognize this and commented on it, but the requestor asked to supply the blocks into a for loop:
Quote:
Here I am trying to get it block by block (From Hi welcome to Bye** is one block) in a temp file by using for loop.
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