search for pattern in column in XSV

xsv-grep.sh

#!/bin/bash

set \
  -o errexit \
  -o pipefail \
  -o noglob \
  -o nounset \

app=$(basename "$0" .sh)

# -----------------------------------------------------------------------------
# usage
# -----------------------------------------------------------------------------

# default options
default_delimiter=','

function usage { cat << EOF
$app

USAGE

  $app [options] column=needle...

DESCRIPTION

  Find needles in columns in XSV formatted input.

  Note: Assumes that XSV formatted input contains a header!

ARGUMENTS

  column=needle         search for needle in column
                        (exact matching!)

OPTIONS

  --delim=x             delimiter aka (field) separator
                        default: '$default_delimiter'

  -?, --help            shows this help text

EXAMPLES

  check if Spectrum Scale filesystem is write-mounted

    mmlsmount gpfs95 -L -Y | $app --delim=: nodeName=node001 mountMode=RW

EOF
}

# -----------------------------------------------------------------------------
# options
# -----------------------------------------------------------------------------

delimiter=$default_delimiter

for arg in "$@"
do
  case "$arg" in
    -\?|--help)
      usage
      exit
      ;;

    --delim=*)
      delimiter=${arg##--delim=}
      shift
      ;;

    --)
      # begin of positional arguments (explicit)
      shift
      break
      ;;

    -*)
      echo "$app: unrecognized option: $arg" >&2
      usage >&2
      exit 2
      ;;

    *)
      # begin of positional arguments (implicit)
      break
      ;;
  esac
done

# -----------------------------------------------------------------------------
# arguments
# -----------------------------------------------------------------------------

columns=()
needles=()

for arg in "$@"
do
  case "$arg" in
    *=*)
      IFS='=' read -r column needle <<< "$arg"
      columns+=("$column")
      needles+=("$needle")
      ;;

    *)
      echo "$app: argument format needs to be: column=needle" >&2
      usage >&2
      exit 2
      ;;
  esac
done

# bail out if there are no arguments
if [[ -z "${columns[*]}" || -z "${needles[*]}" ]]
then
  echo "$app: no arguments given" >&2
  usage >&2
  exit 2
fi

# -----------------------------------------------------------------------------
# app
# -----------------------------------------------------------------------------

awk -F "$delimiter" -v columns="${columns[*]}" -v needles="${needles[*]}" '
  BEGIN {
    # found is our exit status
    found = 1

    # split columns and needles (again)
    split(columns, columns_a, " ")
    split(needles, needles_a, " ")

    # build up searches
    # - columns are the array keys
    # - needles are the array values
    for (i in columns_a) {
      searches[columns_a[i]] = needles_a[i]
    }
  }

  # first line has header
  NR == 1 {
    # associate header name with column number
    for (i=1; i <= NF; i++) {
      header[$i] = i
    }
  }

  # for all lines but header ...
  NR > 1 {
    line_found = 0

    # ... go through each of the searches
    # ... if any do not match
    for (column in searches) {
      if ($(header[column]) != searches[column]) {
        line_found = 1
        break
      }
    }

    if (line_found == 0) {
      # ... if found stop processing
      found = 0
      exit
    }
  }

  END {
    exit found
  }
'