Print line numbers starting at zero using awk

Question

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           gt  actual output txt   whereas my expected output is file txt  How do I print the line numbers starting with zero  0

User · Answer

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

User · Answer

Another option besides awk is nl which allows for options -v for setting starting value and -n  lt lf rf rz gt  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  lt infile gt       other stuff      nl -v 0 -n rz   or simply  nl -v 0 -n rz  lt infile gt    Example   echo  Here  are some  words   gt  words txt   cat words txt   nl -v 0 -n rz  Out   000000      Here 000001      are 000002      some 000003      words

User · Answer

NR starts at 1  so use  awk   print NR-1      0

User · Answer

If Perl is an option  you can try this   perl -ne  printf   s         -1  file      is the line    is the line number

[awk] Print line numbers starting at zero using awk

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