Question

I’m getting a syntax error when running an awk script, the script is:

awk -F\" 'for( i = 1 ; i <= NF; i++){if ($i == "^[0-9]+$"){ gsub(.,,,$1) }}'

A sample of how the actual data may look like is this (enclosed and pipe separated):

"data"|"data"|"data"|"data"|"data"

What i want to do, as you can see from the code is: read all fields, if a field is numeric (will always be decimal), replace the point with a comma.
I have also tried to escape the comma in the gsub function:

awk -F\" 'for( i = 1 ; i <= NF; i++){if ($i == "^[0-9]+$"){ gsub(.,\,,$1) }}'

But its not solving the issue, do you have any idea where the problem is? the comparison against a regex it looks fine, the loop and the if statements also, the error message is

    awk: cmd. line:1: for( i = 1 ; i <= NF; i++){if ($i == "^[0-9]+$"){ gsub(.,,,$1) }}
awk: cmd. line:1: ^ syntax error
awk: cmd. line:1: for( i = 1 ; i <= NF; i++){if ($i == "^[0-9]+$"){ gsub(.,,,$1) }}
awk: cmd. line:1:            ^ syntax error
awk: cmd. line:1: for( i = 1 ; i <= NF; i++){if ($i == "^[0-9]+$"){ gsub(.,,,$1) }}
awk: cmd. line:1:                     ^ syntax error
awk: cmd. line:1: for( i = 1 ; i <= NF; i++){if ($i == "^[0-9]+$"){ gsub(.,,,$1) }}
awk: cmd. line:1:                           ^ syntax error
awk: cmd. line:1: for( i = 1 ; i <= NF; i++){if ($i == "^[0-9]+$"){ gsub(.,,,$1) }}
awk: cmd. line:1:                                                 ^ syntax error
awk: cmd. line:1: for( i = 1 ; i <= NF; i++){if ($i == "^[0-9]+$"){ gsub(.,,,$1) }}
awk: cmd. line:1:                                                          ^ syntax error
awk: cmd. line:1: for( i = 1 ; i <= NF; i++){if ($i == "^[0-9]+$"){ gsub(.,,,$1) }}
awk: cmd. line:1:                                                           ^ syntax error
awk: cmd. line:1: for( i = 1 ; i <= NF; i++){if ($i == "^[0-9]+$"){ gsub(.,,,$1) }}
awk: cmd. line:1:                                                              ^ 1 is invalid as number of arguments for gsub

Answer 1

this line may work for you:

awk  'BEGIN{FS=OFS="\""}{for(i=1;i<=NF;i++)if($i~/[0-9\.]*/)gsub("\\.",",",$i)}1' file

test :

kent$  echo '"1000.18"|"4.8"|"data"|"data"|"3.5"'|awk  'BEGIN{FS=OFS="\""}{for(i=1;i<=NF;i++)if($i~/[0-9\.]*/)gsub("\\.",",",$i)}1'
"1000,18"|"4,8"|"data"|"data"|"3,5"

the problems in your code are:

• your for loop should be wrapped with {}
• you should use ~, not == for regex matching
• even if you used ~, your regex is not correct. ^[0-9]+$match only numbers, 20.8 is not matched. because there is a dot
• in gsub, the first parameter is regex you want to replace. if you simply put a dot in it. it means any character. you have to escape it, to let gsub know that you just want to replace the “dot”.