Tip: Detect Network Connectivity in Bash

Rai    Linux     auto, bash, connection, Linux, network, ping, script

There are times that we are required to check hundreds of servers for network connectivity, and what command comes first in mind when testing network – ping. To help out other system and network administrators out there, here is a quick bash script to ping servers.

#!/bin/bash

SERVERS=server.txt

for i in $(cat $SERVERS)
do
ping -c2 $i > /dev/null

if [ $? -ne 0 ]
then
echo "$i is DOWN"
else
echo "$i is UP"
fi
sleep 3

done

Tip: How to Place Pause in Bash Scripts

Rai    Linux     auto, bash, delete, Linux, pause, script

There some scripts that need human interaction from time to time from confirming certain actions or to warn users that they are about to do something stupid ( “ rm -rf / “, perhaps?). In any case, putting a pause break in a Bash script is a very nifty trick to learn.

This is an example of how to use the Bash built-in command read to put pauses in scripts:

#!/bin/bash

find /home -type f -name "*.txt"
read -p "Press [enter] key to delete *.txt files in /home or CTRL+C to exit"
find /home -type f -name "*.txt" | xargs rm -v

This example script will run the find command and display the results. If user presses the Enter key, the script will remove all files that were found, while pressing CTRL+C will terminate the script.

Here is another variation of the the script:

#!/bin/bash

find /home -type f -name "*.txt"
echo "Press [enter] key to delete *.txt files in /home or CTRL+C to exit"
read contscr
find /home -type f -name "*.txt" | xargs rm -v