UNIX for Dummies Questions & Answers

Dear All,
I have a long list like this:

Code:

337
375
364
389
443
578
1001
20100
.
.
.
.

etc

I would like to substract each value from the first entry which in this case is 337 and report it in a separate column. So the expected output looks like

Code:

337       0
375      -38
364      -27
389      -52
443      -106
578      -241     
1001    -664
20100  -19763
.
.
.
.

etc

Can someone shed some light on how to accomplish this ... to be more precise the first column is actually a feild entry in my file ...... how do I perform calculations on this particular feild and report it as a new column ?

Thanks for your input in advance


Thanx

I think it would be more useful if you provided sample of the real file's data. For this data:

Code:

awk 'NR==1{x=$1}{$2=x-$1}1' file

OK Bartus11,
Here is an part of the real file ....

Code:

common.levure5-6-7-8_SNP_SNP_annotated.gff      file_1  1348
common.levure5-6-8_SNP_SNP_annotated.gff        file_2  1167
common.levure5-6-7_SNP_SNP_annotated.gff        file_3  1125
common.levure5-7-8_SNP_SNP_annotated.gff        file_4  1104
common.levure6-7-8_SNP_SNP_annotated.gff        file_5  1083
common.levure5-6_SNP_SNP_annotated.gff          file_6  952
common.levure5-8_SNP_SNP_annotated.gff          file_7  896
common.levure5-7_SNP_SNP_annotated.gff          file_8  886
common.levure6-8_SNP_SNP_annotated.gff          file_9  872
common.levure7-8_SNP_SNP_annotated.gff          file_10 862
common.levure6-7_SNP_SNP_annotated.gff          file_11 846

So basically what I wanted to do was more complicated ... I give you example output of first 2 lines .... First I want to calculate the number of instances a DIGIT is present in column 1 (which I think is $1) ... so in the first line there are 4 digits 5-6-7-8 and in the lines 2 to 5 there are 3 digits and in the other lines 2 digits (by digits I mean numeric characters) then these values for each line need to be used to divide the last field of the file .... so in line one 1348 should divide by 4, in line two 1167 should divide by 3 and so on. The the results of the division should be displayed in the next column and its not over .... then the first entry of the division which is 337 (obtained by 1348/4) has to be used as a constant to subtract all other entries in the same column below it and reported in yet another column...

my expected output for the first 2 lines as an example is ....

Code:

common.levure5-6-7-8_SNP_SNP_annotated.gff      file_1  1348    337    0
common.levure5-6-8_SNP_SNP_annotated.gff        file_2  1167     389    -52

etc

I just didnt want to ask so many questions so I thought just ask you the last step .... but if you can explain how to do the above especially how to scan for elements of choice in a single field as counting numeric digits in the first feild in this example, that will be a great thing to learn.

Thank you and please make comments on the code if you can kindly provide one

Cheers

using shell script:

make a shell script (shell.sh) which takes 1 argument (data filename)

Code:

count=0
for i in `cat $1`
do
count=`expr $count + 1`
if [ $count -eq 1 ]
then
top=$i
fi
echo $i `expr  $top - $i`

done

then run the script,

Code:

./shell.sh filename

Code:

perl -lnae '$n=$F[0]=~s/\d/$&/g;$div=$F[2]/$n;$first=$div if $.==1;print "$_\t$div\t" . ($first-$div)' file

You can find description of most of the code used here in https://www.unix.com/302503405-post6.html
New things:
$n=$F[0]=~s/\d/$&/gcount number of numeric characters contained in first field and store this count in $n
$first=$div if $.==1assign $div value to $first when first line is being processed ($. contains number of currently processing line)
Rest of the code is just arithmetic operations and output formatting.

@gaurab: Thanks a lot

@Bartus11: You always amaze me with your perl one-liners .... simply awesome and thanks very much for the comments too ..... Honestly u need to tell me / give directions to resources and of how and where I can learn some of this .. Have a great day

"Learning Perl" by Tom Phoenix, Randal L. Schwartz is a good start BTW here is the same logic in AWK:

Code:

awk '{x=$1;n=gsub("[0-9]","",x);div=$3/n;if (NR==1) first=div; print $0"\t"div"\t"first-div}' file