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Shell Programming and Scripting

Conditionally delete last X lines

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# 1  
Old 02-13-2011
Conditionally delete last X lines
delete last X lines,which start with [0-9]+

example file:
Code:
test1
test2
[23] remove1 
[24] remove2

one liner shell is preferred.
# 2  
Old 02-13-2011
so what did you try?
# 3  
Old 02-13-2011
Also, I want a cup of coffee and a croissant!

Why don't you tell us what you have tried so far?
# 4  
Old 02-13-2011
I figured it out, But I don't like the trick of tac.
[Help still needed, Solaris doesn't have tac command.]

Code:
$cat t2
test1
test2
[23] remove1 
test3
[24] remove2
[1] remove

$tac t2 | awk '{ if (($0 ~ /^\[[0-9]+\]/ )&&( flag!=1 )) { } else {print $0; flag=1 } } ' | tac
test1
test2
[23] remove1 
test3

Last edited by honglus; 02-14-2011 at 12:18 AM..
# 5  
Old 02-14-2011
from above sample, what do you need removed? All the lines within [ ] ?

Code:
test1
test2
[23] remove1 
test3
[24] remove2
[1] remove

# 6  
Old 02-14-2011
Could this help you.

Code:
awk '{a[++i]=$0} END{for(j=i;j>=1;j--){print a[j]}}' inputfile | awk '{if (($0 ~ /^\[[0-9]+\]/ )&&( flag!=1 )) { } else {a[++i]=$0;flag=1 } } END{for(j=i;j>=1;j--){print a[j]}}'

# 7  
Old 02-14-2011
Code:
awk '/^\[[0-9]+\]/{s=s (s""?RS:x) $0;next}s""{print s; s=x}1' infile
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