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Full Discussion: Reverse even lines
Top Forums Shell Programming and Scripting Reverse even lines Post 302869631 by vgersh99 on Wednesday 30th of October 2013 04:10:41 PM
Old 10-30-2013
Code:
pesky awk-s - don't flush output  unless you explicitly close the pipped cmd
awk 'NR % 2 {print;next}; {print | "rev";close("rev")}' myfile

Code:
# for every EVEN line
!(FNR%2) {
   # initialize a temp var t to an empty string
   t=""
   # temp var 'l' contains the length of the current record/line
   l=length
   # iterate through the current line assigning the reversed chars to 't'
   for(i=1;i<=l;i++) 
      t=substr($0,i,1) t
   # assign the final reversed record/line back to $0
   $0=t
}
# 1 in awk is default/shortcut to 'print' current/$0 record/line
1


Last edited by vgersh99; 10-30-2013 at 05:23 PM..
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COLORS(3)						   libbash colors Library Manual						 COLORS(3)

NAME
colors -- libbash library for setting tty colors. SYNOPSIS
colorSet <color> colorReset colorPrint [<indent>] <color> <text> colorPrintN [<indent>] <color> <text> DESCRIPTION
General colors is a collection of functions that make it very easy to put colored text on tty. The function list: colorSet Sets the color of the prints to the tty to COLOR colorReset Resets current tty color back to normal colorPrint Prints TEXT in the color COLOR indented by INDENT (without adding a newline) colorPrintN The same as colorPrint, but trailing newline is added Detailed interface description follows. Available colors: Green Red Yellow White The color parameter is non-case-sensitive (i.e. RED, red, ReD, and all the other forms are valid and are the same as Red). FUNCTIONS DESCRIPTIONS
colorSet <color> Sets the current printing color to color. colorReset Resets current tty color back to normal. colorPrint [<indent>] <color> Prints text using the color color indented by indent (without adding a newline). Parameters: <indent> The column to move to before start printing. This parameter is optional. If ommitted - start output from current cursor position. <color> The color to use. <color> The text to print. colorPrintN [<indent>] <color> The same as colorPrint, except a trailing newline is added. EXAMPLES
Printing a green 'Hello World' with a newline: Using colorSet: $ colorSet green $ echo 'Hello World' $ colorReset Using colorPrint: $ colorPrint 'Hello World'; echo Using colorPrintN: $ colorPrintN 'Hello World' AUTHORS
Hai Zaar <haizaar@haizaar.com> Gil Ran <gil@ran4.net> SEE ALSO
ldbash(1), libbash(1) Linux Epoch Linux
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