Question

I have this script that is meant to trim the field specified as argument to the script.
ie sh script.sh file.txt "|" 2

#!/bin/bash
filename="$1"
delim="$2"
arg="$3"
gsubber="\"gsub("^[ \t]*|[ \t]*$","",'\$$arg')\""
myout=`nawk -F"$delim" -v fl="$gsubber" \'{ { fl } }1\' OFS="$delim" "$filename"`
echo "$myout"

So this file ‘file.txt’ as input:

sid|storeNo|latitude
9| gerdy| fd¿kjhn422-405
0000543210 |gfdjk39
gfd|fd||fd

becomes this output:

sid|storeNo|latitude
9|gerdy| fd¿kjhn422-405
0000543210 |gfdjk39
gfd|fd||fd

I get this error:
nawk: syntax error at source line 1
context is

‘ <<<
missing }
nawk: bailing out at source line 1

Once someone can assist with providing the correct syntax, I should have no trouble extending it to support multiple fields. ie sh script.sh file.txt "|" 2 3 could then trim the 2nd and 3rd field only.

Thanks in advance!

Answer 1

Try:

#!/bin/bash

filename=$1
delim=$2
arg=$3
regex='^[ \t]*|[ \t]*$'
myout=$(
  nawk -F"$delim" -v regex="$regex" -v arg="$arg" '
    { gsub(regex, "", $arg) }
    1' OFS="$delim" "$filename"
  )

printf '%s\n' "$myout"

Edit:

In order to handle multiple fields in the arguments (see comments below):

#!/bin/bash

filename=$1 
delim=$2
shift 2
args=$@
regex='^[ \t]*|[ \t]*$'
myout=$(
  nawk -F"$delim" -v regex="$regex" -v args="$args" '{ 
    n = split(args, t, " ")
    for (i = 0; ++i <=n;)
      gsub(regex, "", $t[i]) 
    }1' OFS="$delim" "$filename"
  )

printf '%s\n' "$myout"