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Shell Scripting Discussion Thread
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Apr 2nd, 2008

Urgent: Help on grep the nearest value using bash script

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Hi,

I have a list of data in text files with :-
ColA ColB ColC ColD ColE ColF
12 122 2280 30 0.012987 1.776
13 118 2280 30 0.012987 1.954
14 115 2620 30 0.011321 2.131
15 113 2654 30 0.011177 2.309
16 145 1882 25 0.013110 2.487
17 112 2817 30 0.010537 2.664
18 126 2833 30 0.010479 2.842
19 111 2833 30 0.010479 3.020
16 145 1882 25 0.013110 2.487
17 112 2817 30 0.010537 2.664

How could I grep the nearest number to <=3.000 using bash script?

Means in the end i would like to isolate numbers in ColF which last seen the value <= 3.000 which is

18 126 2833 30 0.010479 2.842

Please help. Thanks.

Last edited by ahjiefreak; Apr 2nd, 2008 at 1:48 am. Reason: Confusion of the question

ahjiefreak

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Apr 3rd, 2008

Re: Urgent: Help on grep the nearest value using bash script

Hey there,

This was bugging me all last night, and I finally figured out what my problem was

This should do the trick for you:

Shell Scripting Syntax (Toggle Plain Text)

awk 'BEGIN {var=3; highest=0}{ j = $NF;if ( j < var && j > highest ) { highest=j} } END {print highest}' YourInputFile

That gave me

2.842

from the text you pasted in this post. There's probably a more elegant solution out there, but this'll do the trick for now

Best wishes

, Mike

eggi

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Posting Whiz

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Apr 3rd, 2008

Re: Urgent: Help on grep the nearest value using bash script

Actually, oops, you can change the

Shell Scripting Syntax (Toggle Plain Text)

j < var

part to

Shell Scripting Syntax (Toggle Plain Text)

j <= var

just noticed that

Shell Scripting Syntax (Toggle Plain Text)

awk 'BEGIN {var=3; highest=0}{ j = $NF;if ( j <= var && j > highest ) { highest=j} } END {print highest}' YourInputFile

, Mike

eggi

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Posting Whiz

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Apr 5th, 2008

Re: Urgent: Help on grep the nearest value using bash script

Shell Scripting Syntax (Toggle Plain Text)
awk '$NF <=3 {a[NR]=$NF;c[a[NR]]=$0}
END{
 n=asort(a,b)
 print c[b[n]] 
}' file
awk '$NF <=3 {a[NR]=$NF;c[a[NR]]=$0}
END{
 n=asort(a,b)
 print c[b[n]] 
}' file

output:

Shell Scripting Syntax (Toggle Plain Text)
# ./test.sh
18 126 2833 30 0.010479 2.842
# ./test.sh
18 126 2833 30 0.010479 2.842

ghostdog74

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Apr 5th, 2008

Re: Urgent: Help on grep the nearest value using bash script

I knew there was a better answer out there

GhostDog74, you are an awk master! If you don't mind me posting this here, could you point me to a good awk tutorial on the web. I'd like to better understand a lot of programmatical aspects of it.

Thanks in advance and good stuff

Cheers,

Mike

eggi

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Apr 5th, 2008

Re: Urgent: Help on grep the nearest value using bash script

Click to Expand / Collapse Quote originally posted by eggi ...

GhostDog74, you are an awk master!

no i am not. there are many who are better

Quote ...

If you don't mind me posting this here, could you point me to a good awk tutorial on the web. I'd like to better understand a lot of programmatical aspects of it.

this is where i learn AWK/SED. Also grymoire is worth a look

ghostdog74

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Apr 6th, 2008

Re: Urgent: Help on grep the nearest value using bash script

Cool,

Thank you very much

I'll definitely check out these links (already adding them to my favorites).

You're very humble and come up with some excellent answers. I'm sure I'll see more in the future and I look forward to it

Thanks, again!

, Mike

eggi

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