File Descriptor Usage

Slug

K104S9K0DD79

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0

Size

1394 B · 54 lines

Expires

never

Last fetch

—

Created

2026-09-07 00:36:00.483

Description

Allocated file handles vs the system max

#!/usr/bin/env bash
# File descriptor usage
# Read-only: /proc/sys/fs/file-nr allocated vs max. Warns at >=80%, critical at >=95%.
# Exit 0 if healthy, 1 if warning, 2 if critical or the proc file is missing.
# Hosted on Runny.sh. Review the script page before you run it.

set -u

status=0
note() { printf '%s\n' "$*"; }
bump() {
  case $1 in
    crit) status=2 ;;
    warn) [ "$status" -lt 1 ] && status=1 ;;
  esac
}

note "=== File descriptor usage ==="
note "Host:     $(hostname 2>/dev/null || printf unknown)"
if [ ! -r /proc/sys/fs/file-nr ]; then
  note "/proc/sys/fs/file-nr is not readable"
  note "Result: CRITICAL"
  exit 2
fi

read -r allocated unused maximum _ < /proc/sys/fs/file-nr
note "Allocated:${allocated}"
note "Unused:   ${unused}"
note "Maximum:  ${maximum}"
if [ -z "${allocated}" ] || [ -z "${maximum}" ] || [ "$maximum" -le 0 ]; then
  note "          WARNING: could not parse file-nr"
  bump warn
else
  pct=$((allocated * 100 / maximum))
  note "Used:     ${pct}%"
  if [ "$pct" -ge 95 ]; then
    note "          CRITICAL: process table file handles are nearly exhausted"
    bump crit
  elif [ "$pct" -ge 80 ]; then
    note "          WARNING: file-handle use is high"
    bump warn
  else
    note "          OK"
  fi
fi
note ""

case $status in
  0) note "Result: HEALTHY" ;;
  1) note "Result: WARNING" ;;
  *) note "Result: CRITICAL" ;;
esac
exit "$status"