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November 22, 2024

Tag: shell

November 12, 2009

a shell script to check if a ipaddress is taken using ping

by viggy — Categories: tech — Tags: , , , Leave a comment

With the help of Abhas Bhaiyya, I could write this shell script which checks if an ipaddress can be pinged.

#!/bin/sh

if [ `ping -c1 192.168.31.31 >/dev/null; echo $?` -eq 1 ]
then
echo “not able to ping”
fi

/dev/null is used here so that the output of the ping command is not compared with 1.
$? gives out the return code of the command.

November 12, 2009

how to get the last argument from the last command in the shell

by viggy — Categories: tech — Tags: , , , , Leave a comment

‘!$’ is the right answer.

For example: $vim test.pl
$chmod +x !$
$./!$

So what is happening above is
first vim test.pl opens a file.
then after you have written a perl script, you would like to make it executable. There is no need for you to specify the file name again. You can just use !$.
In the third command again to execute the file, there is no need to mention the file name again. You just use !$ again.