Sometimes, you find some interesting application/command by accident, and that is just what happened a few days back. Well, I was doing a ssh and as usual made my share of mistake in typing and missed the “h” from the ssh command and saw a list of options instead of my prompt on remote server.
Now, that set me thinking and fond that its a very interesting command that comes with iproute on Fedoara, so if you want this command, then install iproute like this
sudo yum install iproute
and then you can see the help with
By default, without any options you will see a list of all open sockets on your system.
There are a lot of options that you can use and couple of them are very interesting a useful.
For quite sometime now, I was having this issue, that for the home system, I was able to connect to is using ssh but it never worked. Fnally after quite some debugging finally I found that the issue was with thebashrc. So, everytime I had to do a scp I would have to move/rename bashrc and do the reverse action after the scp was done.
Finally today I fixed it and the solution was very simple. I put the offending code or rather complete bashrc in the loop as mentioned below:
1 2 3 4 5 6 7
if [[ $SSH_CLIENT = "" ]
<bashrc code here>
By doing this the <dot>bashrc is never executed when a ssh session is initiated (which is what happens for scp also). 🙂
I was writing a bash script that would do some operations and read and write to file. Seems that that was pretty simple with
1 2 3 4 5
while read line
and then use redirection operations like “>” and “>>” to write to file. Done with the script pretty fast. So far so good, when I went for real life tests, no one was interested in using it, why? Simple, it was simply taking too long. The file was reading about 10K lines and writing about 50 lines and was taking about more than 10 minutes.
So, I sat down to debug what can increase the performance of the script and one change made the difference. The script was taking a lot of time in opening and closing the file. Pretty evident, isn’t it!!!