Update linux_disk_usage.sh to include additional output data and header info

Script now contains a more descriptive header with exit codes, parameters, env vars, etc.

In addition, script now shows the path where disk is mounted and shows consumption in quantity not just percentage.

Author: lravelo

scripts_wip/linux_disk_usage.sh

@@ -1,45 +1,106 @@
-#!/bin/bash
+#!/usr/bin/env bash
+###############################################################################
+# Script Name : linux_disk_usage.sh
+# Description : Used to check the disk usage of mounted Linux filesystems and
+#               return an alert if usage exceeds the specified thresholds.
+#               (Default warning threshold is 75% and default error threshold
+#               is 90%; thresholds can be changed via -w/--warning and -e/--error
+#               flags or the WARNINGVALUE and ERRORVALUE environment variables.)
+#
+# Exit Codes  :
+#   0 - OK       (No thresholds exceeded)
+#   1 - Invalid input / script failure
+#   2 - WARNING  (Warning threshold exceeded)
+#   3 - ERROR    (Error threshold exceeded)
+#
+# Parameters  :
+#   -w, --warning <int>  Warning threshold percentage (default: 75)
+#   -e, --error   <int>  Error threshold percentage   (default: 90)
+#
+# Environment :
+#   WARNINGVALUE  Alternative warning threshold
+#   ERRORVALUE    Alternative error threshold
+#
+# Examples    :
+#   ./linux_disk_usage.sh -w 70 -e 85
+#   WARNINGVALUE=70 ERRORVALUE=85 ./linux_disk_usage.sh
+#
+# Compatibility:
+#   Linux (GNU coreutils)
+#
+# Repository  : https://github.com/amidaware/community-scripts
+# Category    : TRMM (nix):System Monitoring
+# Version     : 1.0
+# Last Updated: 2026-02-06
+###############################################################################
 
-# This script will check disk usage on Linux filesystems. It will give a warning if the usage is over the warning threshold and an error if the usage is over the error threshold
-# The env variables "ERRORVALUE" and "WARNINGVALUE" should be passed in the script in the format: ERRORVALUE=xx and WARNINGVALUE=xx.
-# If the env variables are not passed, the defaults of 90 75 will be applied
+# ------------------------------- Defaults ---------------------------------- #
+WARNINGVALUE="${WARNINGVALUE:-75}"
+ERRORVALUE="${ERRORVALUE:-90}"
 
-if [ -z "$ERRORVALUE" ];
-then
-    ERRORVALUE=90
-fi
+# Filesystems to exclude (regex)
+EXCLUDE_FS_REGEX='^(tmpfs|devtmpfs|overlay|squashfs|ramfs|/dev/loop)'
 
-if [ -z "$WARNINGVALUE" ];
-then
-    WARNINGVALUE=75
-fi
+# ----------------------------- Arg Parsing --------------------------------- #
+while [[ $# -gt 0 ]]; do
+    case "$1" in
+        -w|--warning)
+            WARNINGVALUE="$2"
+            shift 2
+            ;;
+        -e|--error)
+            ERRORVALUE="$2"
+            shift 2
+            ;;
+        *)
+            echo "ERROR: Unknown argument: $1"
+            exit 1
+            ;;
+    esac
+done
 
-# parse disk usage percentages
-ERROROUTCODE=0
-WARNINGOUTCODE=0
-for line in $(df -hP | egrep '^/dev/[^loop]' | awk '{ print $1 "_:_" $5 }')
-do
-    FILESYSTEM=$(echo "$line" | awk -F"_:_" '{ print $1 }')
-    DISK_USAGE=$(echo "$line" | awk -F"_:_" '{ print $2 }' | cut -d'%' -f1 )
-
-    if [ $DISK_USAGE -ge $ERRORVALUE ]; then
-        echo -e "Error!" "$FILESYSTEM is $DISK_USAGE% used. Error threshold is $ERRORVALUE%"
-        ERROROUTCODE=1
-    elif [ $DISK_USAGE -ge $WARNINGVALUE ]; then
-        echo -e "Warning!" "$FILESYSTEM is $DISK_USAGE% used. Warning threshold is $WARNINGVALUE%"
-        WARNINGOUTCODE=1
-    else
-        echo "$FILESYSTEM disk usage okay at $DISK_USAGE%"
+# ---------------------------- Validation ----------------------------------- #
+for val in "$WARNINGVALUE" "$ERRORVALUE"; do
+    if ! [[ "$val" =~ ^[0-9]+$ ]]; then
+        echo "ERROR: Threshold values must be integers"
+        exit 1
     fi
 done
 
-if [ $ERROROUTCODE -gt 0 ]; then
-    echo "ERROR. One or more disks are critically low on space."
+if (( WARNINGVALUE >= ERRORVALUE )); then
+    echo "ERROR: Warning threshold must be less than error threshold"
     exit 1
 fi
-if [ $WARNINGOUTCODE -gt 0 ]; then
-    echo "WARNING. One or more disks are getting low on space."
-    exit 2
-else
-    exit 0
-fi
+
+command -v df >/dev/null 2>&1 || {
+    echo "ERROR: Required command 'df' not found"
+    exit 1
+}
+
+# ----------------------------- Execution ----------------------------------- #
+result=0
+
+while IFS='|' read -r filesystem mountpoint used size usage; do
+    usage="${usage%\%}"
+
+    if (( usage >= ERRORVALUE )); then
+        echo "ERROR: $filesystem mounted on $mountpoint is ${usage}% used (${used}/${size}) (>= ${ERRORVALUE}%)"
+        result=3
+    elif (( usage >= WARNINGVALUE )); then
+        [[ $result -lt 2 ]] && result=2
+        echo "WARNING: $filesystem mounted on $mountpoint is ${usage}% used (${used}/${size}) (>= ${WARNINGVALUE}%)"
+    else
+        echo "OK: $filesystem mounted on $mountpoint is ${usage}% used (${used}/${size})"
+    fi
+done < <(
+    df --output=source,fstype,target,used,size,pcent -h \
+    | tail -n +2 \
+    | awk -v exclude="$EXCLUDE_FS_REGEX" '
+        $1 ~ /^\/dev\// &&
+        $2 !~ exclude {
+            print $1 "|" $3 "|" $4 "|" $5 "|" $6
+        }
+    '
+)
+
+exit "$result"