Ubuntu – How to use double substitution in awk

awkbashcommand linescripts

To print the fields at 29th column in two files I used

paste <(awk -F, '{print $29}' PreRefFile.csv) <(awk -F, '{print $29}' Txlog.csv)

This worked fine.
To print all the fields starting from 29 to 189. I wrote a script as follows

 y=29
 while [ $y -le 189 ]
 do
   x="\$$y"
   paste <(awk -F, '{print "'"$x"'"}' PreRefFile.csv) <(awk -F, '{print "'"$x"'"}' Txlog.csv)
   y=`expr $y + 1`
 done

Here the value of x is replaced by "$" followed by number (First round of substitution) and it is printing "$" follwed by that number instead of printing the field at that location. How to get that field in this way.
I cannot write the same line for so many times. Suggest a method to proceed.

Also suggest another tool to do this, other than awk

Best Answer

All what you need is the power of awk and a for Statement:

paste <(awk -F, '{ for (i=29;i<=188; i++) print $i }' PreRefFile.csv) <(awk -F, '{ for (i= 29;i<= 188;i++) print $i }' Txlog.csv)

My test case:

paste <(awk -F, '{ for (i=2;i<=3;i++) print $i }' foo1) <(awk -F, '{ for (i=2;i<=3;i++) print $i }' foo2)

File foo1:

1,2,3,4,5,6
7,8,9,10,11,12

File foo2:

a,b,c,d,e,f,g
A,B,C,D,E,F,G

Output:

Related Solutions

Ubuntu – How to compare float variables in awk

awk compares floating point numbers:

I just wrote a new script:

paste \
    <(awk -F, '{print $29}' file1 ) \
    <(awk -F, '{print $29}' file2 ) \
    | awk '{print $1; print $2; print ($1==$2)?"match" :"mismatch"}'

If you do not like breaks, then use printf instead of print.

Example

Input files

cat file1

12,2,12,12,12,12,3,2,53,6,5474,346,567,6578,89,7689,7,987,69869,1,4,5,4,3,4,2,6,21,832.9,9,2
12,2,12,12,12,12,3,2,53,6,5474,346,567,6578,89,7689,7,987,69869,1,4,5,4,3,4,2,6,21,12.329,9,2

cat file2

12,2,12,12,12,12,3,2,53,6,5474,346,567,6578,89,7689,7,987,69869,1,4,5,4,3,4,2,6,21,832.9000,9,2
12,2,12,12,12,12,3,2,53,6,5474,346,567,6578,89,7689,7,987,69869,1,4,5,4,3,4,2,6,21,832.9000,9,2

Output

% paste <(awk -F, '{print $29}' file1 ) <(awk -F, '{print $29}' file2 ) | awk '{print $1; print $2; print ($1==$2)?"match" :"mismatch"}'

832.9
832.9000
match
12.329
832.9000
mismatch

Ubuntu – Cannot use awk pipe output

awk buffers the STDOUT stream, you need to flush the STDOUT, make it flush the stream using the fflush() function of GNU awk:

my_function_with_ouput | awk '!seen[$0]++ {print; fflush()}' | while ...

If you don't have gawk, take help from stdbuf, unbuffered STDOUT:

my_function_with_ouput | stdbuf -o0 awk '!seen[$0]++' | while ...

or make STDOUT line buffered:

my_function_with_ouput | stdbuf -oL awk '!seen[$0]++' | while ...

Best Answer

Related Solutions

Ubuntu – How to compare float variables in awk

Ubuntu – Cannot use awk pipe output

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