Re: print N times

 > - When P has run 4 times, PatSpace has \n\n\n\n, s substitutes \n #4, T 
does not loop, sed exits.
 

 After running 4 times, the PatSpace would have (the ^ $ are placeholders)
 

          ^abcd\n\n\n\n$
 

 

 > $ N=4
 > $ echo abcd | sed -e ":k x; /z\{$N\}/ d" -e 's/$/z/; x; p; bk'
 

 I prefer the vertical form of sed one-liners as they are somewhat
 self-documenting and appear like a regular programming language.
 The horizontal sed one liners are hieroglyphics to the beginner;
 and might also help in putting off the adoption of sed by prospective
 users.
 

 For example, the above when re-phrased in vertical style,
 would appear as:
 

 echo "abcd" |
 sed -e "
 ...:loop
 ......x
 ........./.\{$N\}/d
 ........s/^/^/
 ......x
 ......p
 ...bloop
 "
 

 I have used the leading dots, because OTW the yahoo
 mailer collapses the indenting.
 

 Label names are chosen meaningfully so as to heighten
 legibility, instead of uni-letter names.
 

 From the layout we can make out that there is a do-while loop
 and another indent is to imply that we are operating on the hold
 space in that level.
 

 While not completely explanatory, but it's incrementally more helpful.
 

 -Rakesh
 

 

 
---In [email protected], <dgoldman@...> wrote :

 That's very clever. Here is my best understanding how Rakesh's solution 
 works, please correct me if I didn't get it right.
 
 $ N=4
 $ echo abcd | sed -n ":k G; P; s/\n/&/$N; Tk"
 abcd
 abcd
 abcd
 abcd
 
 - Each time through loop, P prints abcd (line #1 of PatSpace).
 - For counter, G appends \n to PatSpace each time through loop.
 - Seems like the order of G and P does not matter.
 - Normally, s does not substitute, so T loops.
 - When P has run 4 times, PatSpace has \n\n\n\n, s substitutes \n #4, T 
 does not loop, sed exits.
 
 -------------------
 
 I made a simpler version of Davide's solution, I think it still works, 
 he already explained how the solution works.
 
 $ N=4
 $ echo abcd | sed -e ":k x; /z\{$N\}/ d" -e 's/$/z/; x; p; bk'
 abcd
 abcd
 abcd
 abcd
 
 ---------------------
 
 Daniel
 
 >
 >
 > We can simplify the sed code a bit , since the pattern space
 > gets loaded by input.
 > Note: The $N even though it looks like a valid sed syntax, but
 > here it is a shell variable N, storing the number of times
 > to print the string "abcd". N > 0
 >
 >
 > sed -ne "
 >
 > :loop
 > G;P
 > s/\n/&/$N
 > Tloop
 > "
 >
 >
 >
 >
 >
 > [Non-text portions of this message have been removed]
 >
 >
 >
 > ------------------------------------
 > Posted by: sharma__r@... mailto:sharma__r@...
 > ------------------------------------
 > 

  


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