Monitor UNIX / Linux Server Disk Space with Shell Script

in Categories Monitoring last updated April 10, 2008

Shell script to monitor or watch the disk space and send an email alert if the (free avilable) percentage of space is >= 90%

#!/bin/sh
# Shell script to monitor or watch the disk space
# It will send an email to $ADMIN, if the (free avilable) percentage 
# of space is >= 90% 
# -------------------------------------------------------------------------
# Copyright (c) 2005 nixCraft project <http://cyberciti.biz/fb/>
# This script is licensed under GNU GPL version 2.0 or above
# -------------------------------------------------------------------------
# This script is part of nixCraft shell script collection (NSSC)
# Visit http://bash.cyberciti.biz/ for more information.
# ----------------------------------------------------------------------
# Linux shell script to watch disk space (should work on other UNIX oses )
# SEE URL: http://www.cyberciti.biz/tips/shell-script-to-watch-the-disk-space.html
# set admin email so that you can get email
ADMIN="me@somewher.com"
# set alert level 90% is default
ALERT=90
df -H | grep -vE '^Filesystem|tmpfs|cdrom' | awk '{ print $5 " " $1 }' | while read output;
do
  #echo $output
  usep=$(echo $output | awk '{ print $1}' | cut -d'%' -f1  )
  partition=$(echo $output | awk '{ print $2 }' )
  if [ $usep -ge $ALERT ]; then
    echo "Running out of space \"$partition ($usep%)\" on $(hostname) as on $(date)" | 
     mail -s "Alert: Almost out of disk space $usep" $ADMIN
  fi
done

Shell Script Which Gets Executed With Greetings – The Moment User Logs In

in Categories Time and Date last updated April 5, 2008

Write shell script which gets executed the moment user logs in, it should greet user

Script first finds out current hour using date command

Depend upon time of the day, it will say Good morning or Good afternoon to user.

Open your bash / shell startup file i.e. profile file – ~/.bash_profile and put path to this script in file as follow:
/home/you/path/to/script

Sample shell script to greet user

#!/bin/bash
# Shell program which gets executed the moment the user logs in, it should
# display the message "Good morning", "Good Afternoon", or "Good Evening"
# depnding upon the time which the user logs in.
# =====================================================================
# Q. How to run this script as soon as user logs in?
# A. Open your bash startup file aka profile file - ~/.bash_profile
# and put path to this script in file as follow:
# . /path/to/greetings.sh
# -----------------------------------------------
# Copyright (c) 2005 nixCraft project <http://cyberciti.biz/fb/>
# This script is licensed under GNU GPL version 2.0 or above
# -------------------------------------------------------------------------
# This script is part of nixCraft shell script collection (NSSC)
# Visit http://bash.cyberciti.biz/ for more information.
# -------------------------------------------------------------------------
 
# get current hour (24 clock format i.e. 0-23)
hour=$(date +"%H")
 
# if it is midnight to midafternoon will say G'morning
if [ $hour -ge 0 -a $hour -lt 12 ]
then
  greet="Good Morning, $USER"
# if it is midafternoon to evening ( before 6 pm) will say G'noon
elif [ $hour -ge 12 -a $hour -lt 18 ] 
then
  greet="Good Afternoon, $USER"
else # it is good evening till midnight
  greet="Good evening, $USER"
fi
 
# display greet
echo $greet

Shell Script to display current date, calendar, and the number of user logged

in Categories Academic last updated April 3, 2008

This script use the concept of command substitution. It allows allows the output of a command to replace the command name. There are two forms:

$(command)

or

`command`

Bash shell performs the expansion by executing command and replacing the command substitution with the standard output of the command, with any trailing newlines deleted. Embedded newlines are not deleted, but they may be removed during word splitting.

For example you can execute date command to display todays date and then set a variable called NOW:
NOW=$(date)
or
NOW=`date`
To display back variable value simply run echo command:
echo $NOW

Sample Shell Script

#!/bin/bash
# Shell script to display current date, calendar, and the number of
# user logged.
# -------------------------------------------------------------------------
# Copyright (c) 2005 nixCraft project <http://cyberciti.biz/fb/>
# This script is licensed under GNU GPL version 2.0 or above
# -------------------------------------------------------------------------
# This script is part of nixCraft shell script collection (NSSC)
# Visit http://bash.cyberciti.biz/ for more information.
# ----------------------------------------------------------------------
echo "Today is $(date)"
echo ""
 
echo "Calendar :"
cal
 
echo "Number of users currently logged : $(who | wc -l)"

Script to Store given command and execute them

in Categories Academic last updated April 3, 2008

Write script to store the following command and execute them:
a) date
b) echo “Message”
c) cal

#!/bin/bash
# Script to Store given command and execute them
# -------------------------------------------------------------------------
# Copyright (c) 2005 nixCraft project <http://cyberciti.biz/fb/>
# This script is licensed under GNU GPL version 2.0 or above
# -------------------------------------------------------------------------
# This script is part of nixCraft shell script collection (NSSC)
# Visit http://bash.cyberciti.biz/ for more information.
# ----------------------------------------------------------------------
date
cal
echo "Hello Friends"