rearrange columns in a csv file

csvmove

#!/bin/bash

# csvmove
# rearrange columns of a csv file read from stdin

# usage: csvmove column [column...]
# column arguments can be formatted like this: 1,3,3,7-10,32
# any column can be repeated more than once or skipped

if (( ! $# )); then
  echo "Missing argument" >&2
  exit 1
fi

# expand a range
for range; do
  IFS=, read -ra input <<< "$range"
  for i in "${input[@]}"; do
    if [[ $i =~ ^[[:digit:]]+-[[:digit:]]+$ ]]; then
      eval "nums+=({${i%-*}..${i#*-}})"
    elif [[ $i =~ [[:digit:]]+ ]]; then
      nums+=("$i")
    else
      echo "Invalid number or range: $i" >&2
      exit 1
    fi
  done
done

# needs gnu awk for FPAT
awk '
BEGIN {
  FPAT = "([^,]*)|(\"[^\"]+\")"
  for (i = 1; i < ARGC; i++) column[++j] = ARGV[i]
  ARGC = 1
}
{
  for (i = 1; i < j; i++) printf ("%s,", $column[i])
  print $column[i]
}
' "${nums[@]}"