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perl or sed replace lines only if for all files

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# 1  
Old 04-12-2011
perl or sed replace lines only if for all files
Hi Everyone,

Code:
[root@]# cat 3
a
b
[root@]# cat 4
a
b

[root@]# perl -p -i -e "s/.*/c/ if $.==2" *

[root@]# cat 3
a
c
[root@]# cat 4
a
b

how to make the file "4", the 2nd line also change to "c"? i thought i already use "*" for all files. Please advice.

Thanks
# 2  
Old 04-12-2011
Try:
Code:
for i in *; do perl -p -i -e "s/.*/c/ if $.==2" $i; done

This User Gave Thanks to bartus11 For This Post:
jimmy_y
# 3  
Old 04-12-2011
the variable $. will not reset to 1 once the next file starts. It will continue counting.
This User Gave Thanks to kurumi For This Post:
jimmy_y
# 4  
Old 04-12-2011
Code:
perl -i -pe'
  s/.*/c/ if $. == 2;
  close ARGV if eof;
  '  *

# 5  
Old 04-12-2011
Ruby(1.9+)
Code:
$ ruby -i -pne '$_="c\n" if $.==2; ARGF.close if ARGF.eof'  3 4

This User Gave Thanks to kurumi For This Post:
jimmy_y
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