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Any solution to get previous line in awk

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# 1  
Old 08-18-2013
Any solution to get previous line in awk
Hi all...

Is there any solution to do the reverse process of getline ?

Thanks in advance.
# 2  
Old 08-18-2013
Why not only save line to variable ?
Code:
{ 
  # save current line for later using
   prev=$0
}

If need previous line, you can use variable or return it to the variable $0
Code:
{ # some rule
     # save current for later using
     curr=$0
     # take previous line
     $0=prev
     # do something
     ...
     # and return current line
     $0=curr
}

# 3  
Old 08-18-2013
Thanks a lot...
# 4  
Old 08-18-2013
Prints line before pattern
Code:
awk '/pattern/ {print a}{a=$0}'

# 5  
Old 08-19-2013
Hi Jotne,

Could you please explain the code?

Thanks!
# 6  
Old 08-19-2013
Code:
awk '
	/pattern/ {print a}
	{a=$0}'

Running on a file:
Line1: Does it contain "pattern", yes print a (here a will be empty), no continue
a=Line1
Line2: Does it contain "pattern", yes print a (her a contial line1), no continue
a=Line2
Line3: Does it contain "pattern", yes print a (her a contial line2), no continue
a=Line3

So a does always contain previous line.
This User Gave Thanks to Jotne For This Post:
krishmaths
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