Sed and Awk to Print Ranges
Dec 27, 2019sed and awk are very powerful tools that would yield results unlike anything else in *Nix.
Although one could certainly create constructs within say a bash script that would give it further fuel, it comes handy to have it as it’s always the case: available, for even other menial tasks.
Printing a given range of lines would undoubtedly come practical during those times when simply displaying them directly by invoking the manual is proven not to be the most straightforward method.
So for this purpose both sed and awk serve me well.
If I were to invoke with sed a certain range of lines to print say from the XParseGeometry manual or from any other file on the system, filtering it out gives - as the proverbial saying goes - power for the money.
Yes, it helps to have the entire man pages on the terminal, but it wouldn’t filter out the results as I have wanted it to. One may try by using grep but I wasn’t interested this time around to use it.
So
man XParseGeometry | awk 'NR==20,NR==40'
would hence return:
display Specifies the connection to the X server.
fheight
fwidth Specify the font height and width in pixels (increment
size).
parsestring
Specifies the string you want to parse.
screen Specifies the screen.
width_return
height_return
Return the width and height determined.
xadder
yadder Specify additional interior padding needed in the win‐
dow.
x_return
returned what I was after..
With sed things are perhps easier, and a great many users recommend to go this route for simple tasks such as the one I usually encounter.
on the terminal
man XParseGeometry | sed -n '20,40'p
would rightly return:
display Specifies the connection to the X server.
fheight
fwidth Specify the font height and width in pixels (increment
size).
parsestring
Specifies the string you want to parse.
screen Specifies the screen.
width_return
height_return
Return the width and height determined.
xadder
yadder Specify additional interior padding needed in the win‐
dow.
x_return
which gives me exactly what I was after….
Of course, the magic of Unix doesn’t stop there. One could further delve into even more commands to give both sed and awk an unimaginable power for pattern searching without having to entirely grep it…
Having other simple tasks such as looking up particular pattern on a given file, is much more easier which could print out the results satisfactorily….
for a given file x
sed -n '2,4'p <filename>
and through awk a simple
awk 'NR==<range>,NR==<range>' <filename>
should suffice.
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