Can anyone tell me how to print line numbers including zero using awk?
Here is my input file stackfile2.txt
when I run the below awk command I get actual_output.txt
awk '{print NR,$0}' stackfile2.txt | tr " ", "," > actual_output.txt whereas my expected output is file.txt
How do I print the line numbers starting with zero (0)?
NR starts at 1, so use
awk '{print NR-1 "," $0}' Using awk.
i starts at 0, i++ will increment the value of i, but return the original value that i held before being incremented.
awk '{print i++ "," $0}' file Another option besides awk is nl which allows for options -v for setting starting value and -n <lf,rf,rz> for left, right and right with leading zeros justified. You can also include -s for a field separator such as -s "," for comma separation between line numbers and your data.
In a Unix environment, this can be done as
cat <infile> | ...other stuff... | nl -v 0 -n rz or simply
nl -v 0 -n rz <infile> Example:
echo "Here are some words" > words.txt cat words.txt | nl -v 0 -n rz
Out:
000000 Here 000001 are 000002 some 000003 words If Perl is an option, you can try this:
perl -ne 'printf "%s,$_" , $.-1' file $_ is the line$. is the line number