diskspace.sh

#! /bin/bash

# Low Disk Space Notifier
#   By Sophie F.
#

# Threshold percent
# If percent usage > than $percent, notify
percent=97
# Email address to receive alert email
mailto="root@Zenobia"

# List of all block devices
    df_output=$(df -Ph | grep -E "/dev/sd.*|/dev/mmcblk.*")
# df command output heading
    df_heading=$(df -lh | head -1)
# Block devices (/dev/... column)
    dev_name=($(echo -e "$df_output" | awk '{ print $1 }'))
# Mount points column
    mounts=($(echo -e "$df_output" | awk '{ print $6 }'))
# Percent free space column
    free_space=($(echo -e "$df_output" | awk '{ print $5 }' | tr -d '%'))

# For each line in $free_space, if $j > $percent, warn user
    for j in "${free_space[@]}"; do
        if [[ "$j" > "$percent" ]]; then
            # Used to match each line with used space > $percent
            line_num=$(echo "$df_output" | grep -inw "$j" | cut -d: -f1)
            # df line of drive info, with line number removed
            j_df_line=$(echo "$df_output" | sed -n $line_num'p' | cut -d: -f2-)
            # Percentage of used spaced
            j_used_space=$(echo -e "$df_output" | sed -n $line_num'p' | awk '{ print $5 }' | tr -d '%')
            # Percentage of free space
            j_free_space=$((100-$j_used_space))
            # Mount point of device
            j_mount_point=$(echo -e "$df_output" | sed -n $line_num'p' | awk '{ print $6 }')
            # Name of device (e.g. /dev/sda)
            j_dev_name=$(echo -e "$df_output" | sed -n $line_num'p' | awk '{ print $1 }' )

            echo "$0: $(hostname): $j_dev_name has $j_free_space% free space!"
            echo -e "$df_heading\n$j_df_line\n\n$(date)" | mail -s "$0: $(hostname): Low disk space on $j_dev_name" "$mailto"
        fi
    done
exit 0