Linux CentOS 7 - Basic scripting

Linux CentOS 7 - Basic scripting

Configure a bash script called  foo.sh; this script reads an input parameter: if the input is "A", it returns "B"; if the input is "B", it returns "A"; otherwise it shows the message "usage foo.sh A|B"

On system1

Edit the file:
# vim /root/foo.sh

#!/bin/bash

if [ "$1" == "A" ]; then

echo "B"

elif [ "$1" == "B" ]; then

echo "A"

            else

echo "/root/foo.sh A|B"

fi

Change the permissions to make it executable by all;

# chmod a+x foo.sh

Test it:
# ./foo.sh A

B


Configure a script called makeusers.sh which reads a list of users from a file and creates those users with the /bin/false shell;
 

On system 1

Edit the script

vim makeusers.sh

#!/bin/bash
if [ $# = 0 ]; then
echo "usage makeusers.sh <users file>"
exit 1
elif [ -f $1 ]; then
for i in `cat $1`; do useradd $i -s /bin/false; done
exit 0
else echo "file not found"
fi

Change the permissions of the script

chmod a+x makeusers.txt

Edit the users file list
vim users.txt
ramu
tom
ben
sam
lory
natasha  

Test the script
 ./makeusers.sh users.txt

Verify it has worked propoerly:
cat /etc/passwd