The Danesh Project » Linux Tips http://thedaneshproject.com Knowledge bling's the finer things in life. Tue, 15 May 2012 21:00:31 +0000 en hourly 1 http://wordpress.org/?v=3.3.2 Linux Tip #9: Create multiple folder or files http://thedaneshproject.com/posts/linux-tip-9-create-multiple-folder-or-files/ http://thedaneshproject.com/posts/linux-tip-9-create-multiple-folder-or-files/#comments Thu, 02 Jul 2009 00:00:00 +0000 Danesh http://thedaneshproject.com/posts/linux-tip-9-create-multiple-folder-or-files/ Sometime it’s necessary for you to create multiple folders or files. This is normally the case for me when I’m working with the clusters at my work place. Fortunately, In Linux this is easy.

Using the “for loop”, one could easily put together a one-liner to see results. See sample below.

The initial “ls” shows that the directory is empty.

[root@abubu test]# ls -l
total 0

Now, make the magic happens. Run “for ((i=1;i<=10;i++)); do mkdir ./folder-$i; done”

[root@abubu test]# for ((i=1;i<=10;i++)); do mkdir ./folder-$i; done

Now, “ls” will give you 10 folders. ;)

[root@abubu test]# ls -l
drwxr-xr-x 2 root root 4096 Jun 30 15:49 folder-1
drwxr-xr-x 2 root root 4096 Jun 30 15:49 folder-10
drwxr-xr-x 2 root root 4096 Jun 30 15:49 folder-2
drwxr-xr-x 2 root root 4096 Jun 30 15:49 folder-3
drwxr-xr-x 2 root root 4096 Jun 30 15:49 folder-4
drwxr-xr-x 2 root root 4096 Jun 30 15:49 folder-5
drwxr-xr-x 2 root root 4096 Jun 30 15:49 folder-6
drwxr-xr-x 2 root root 4096 Jun 30 15:49 folder-7
drwxr-xr-x 2 root root 4096 Jun 30 15:49 folder-8
drwxr-xr-x 2 root root 4096 Jun 30 15:49 folder-9
total 40
[root@abubu test]#

This is just one way to do this. Please feel free to comment if you know a better way.

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If you’re running grep on a large file with multipled results, highlighting your results would really easy on your eyes.

Here’s how;

Export the “GREP_OPTIONS” environment variable to include “–color=auto”. Run the export command below.

export GREP_OPTIONS='--color=auto'

Once you’ve executed the command, run a simple grep to see the highlights in action.

Red is the default highlight color. I’ll cover setting custom colors in a future post.

Similar Posts:]]> http://thedaneshproject.com/posts/linux-tip-8-grep-with-color/feed/ 0 Linux Tip #7: Disable auto logout in C Shell (csh) http://thedaneshproject.com/posts/linux-tip-7-disable-auto-logout-in-c-shell-csh/ http://thedaneshproject.com/posts/linux-tip-7-disable-auto-logout-in-c-shell-csh/#comments Wed, 20 May 2009 18:24:10 +0000 Danesh http://thedaneshproject.com/?p=1469 Run the “set autologout=[n]” command to enable or disable the autologout feature in C Shell (csh)

Setting autologout to “0″ will disable the autologout feature.

set autologout=0

The first line below will set the autologout period to 1 minute and the second line will be 5 minutes. If there is no activity for the set time, you will automatically be logged off from yoru C Shell (csh) session.

set autologout=1

set autologout=5

Similar Posts:]]> http://thedaneshproject.com/posts/linux-tip-7-disable-auto-logout-in-c-shell-csh/feed/ 0 Linux Tip #6: Download with cURL http://thedaneshproject.com/posts/linux-tip-6-download-with-curl/ http://thedaneshproject.com/posts/linux-tip-6-download-with-curl/#comments Fri, 24 Apr 2009 01:00:31 +0000 Danesh http://thedaneshproject.com/?p=1412 Here’s how to download a file using cURL.

curl -O [full url to file]

curl -O http://downloads.wordpress.org/plugin/simple-tags.1.6.6.zip

Sample Output;

[root@kmon01 bin]# curl -O http://downloads.wordpress.org/plugin/simple-tags.1.6.6.zip
% Total % Received % Xferd Average Speed Time Time Time Current
Dload Upload Total Spent Left Speed
100 585k 0 585k 0 0 95317 0 --:--:-- 0:00:06 --:--:-- 120k

Similar Posts:]]> http://thedaneshproject.com/posts/linux-tip-6-download-with-curl/feed/ 0 Linux Tip #5: Reload you /etc/inittab file http://thedaneshproject.com/posts/linux-tip-5-reload-you-etcinittab-file/ http://thedaneshproject.com/posts/linux-tip-5-reload-you-etcinittab-file/#comments Tue, 14 Apr 2009 11:19:10 +0000 Danesh http://thedaneshproject.com/?p=1385 You made changes to your /etc/inittab file but can’t effort any downtime.

There’s a simple trick to reload and apply changes in your /etc/inittab file without a reboot.

Run “init q” or “init Q”

[root@snoopy ~]# init q
[root@snoopy ~]#
[root@snoopy ~]# init Q
[root@snoopy ~]#

Similar Posts:]]> http://thedaneshproject.com/posts/linux-tip-5-reload-you-etcinittab-file/feed/ 0 Linux Tip #4: Simple sort with the sort command http://thedaneshproject.com/posts/linux-tip-4-simple-sort-with-the-sort-command/ http://thedaneshproject.com/posts/linux-tip-4-simple-sort-with-the-sort-command/#comments Fri, 27 Mar 2009 08:41:02 +0000 Danesh http://thedaneshproject.com/?p=1332 You can easily sort your outputs in Linux using the “sort” command. Simply pipe “|” your output to a “sort” command and you should see the sorted results.

See sample usage below. This is just to start off, I’ve cover more in future posts.

[root@hantu ~]# cat numbers
5
4
3
2
1
0
6
7
8
9

[root@hantu ~]# cat numbers | sort
0
1
2
3
4
5
6
7
8
9

[root@hantu ~]# cat numbers | sort -r
9
8
7
6
5
4
3
2
1
0

Happy sorting!!

Similar Posts:]]> http://thedaneshproject.com/posts/linux-tip-4-simple-sort-with-the-sort-command/feed/ 0 Linux Tip #3: System uptime with uptime http://thedaneshproject.com/posts/linux-tip-3-system-uptime-with-uptime/ http://thedaneshproject.com/posts/linux-tip-3-system-uptime-with-uptime/#comments Mon, 23 Mar 2009 13:03:25 +0000 Danesh http://thedaneshproject.com/?p=1317 Want to know how long your Linux box has been up for?

Simple, just run the “uptime” command and you will be rewarded with the answer plus a bit more.

8:58pm  up  19:54,  1 user,  load average: 0.47, 0.62, 0.35

Above is the typical reply from uptime. On the left is the current time, followed by the system’s uptime, logged in users and finally the system’s load average.

Sample output;

danesh@pandora:~> uptime
8:58pm  up  19:54,  1 user,  load average: 0.47, 0.62, 0.35

Similar Posts:]]> http://thedaneshproject.com/posts/linux-tip-3-system-uptime-with-uptime/feed/ 0 Linux Tip #2: Get your PID with $$ http://thedaneshproject.com/posts/linux-tip-2-get-your-pid-with/ http://thedaneshproject.com/posts/linux-tip-2-get-your-pid-with/#comments Tue, 17 Mar 2009 02:00:11 +0000 Danesh http://thedaneshproject.com/?p=1311 “$$” is a useful Linux variable you could use in your script to get it’s PID. The “$$” variable always holds the PID of the executing process.

Why do you need it? Maybe to check if the script is already running? This is what I normally use it for.

Sample Script;

#!/bin/bash
echo "My PID is $$"
sleep 2

Sample Output;

[root@keke ~]# ./test1.sh
My PID is 8909

Similar Posts:]]> http://thedaneshproject.com/posts/linux-tip-2-get-your-pid-with/feed/ 0 Linux Tip #1: Live monitoring with tail http://thedaneshproject.com/posts/linux-tip-1-live-monitoring-with-tail/ http://thedaneshproject.com/posts/linux-tip-1-live-monitoring-with-tail/#comments Mon, 16 Mar 2009 04:40:17 +0000 Danesh http://thedaneshproject.com/?p=1309 This is something every Linux admin or Linux superuser probably already knows and uses everyday.

The “tail -f” command monitors a file and tracks any changes to it. As changes are made to the monitored file the “tail” command will print them on screen. Live monitoring basically…..

tail -f [log file]

Sample output;

[root@keke ~]# tail -f /var/log/messages

Mar 16 11:06:39 keke dhcpd: DHCPREQUEST for 172.28.6.233 from 00:1b:78:d2:bc:0e via eth0
Mar 16 11:06:39 keke dhcpd: DHCPACK on 172.28.6.233 to 00:1b:78:d2:bc:0e via eth0
Mar 16 11:06:39 abubu dhclient: DHCPREQUEST on eth0 to 172.28.1.41 port 67
Mar 16 11:06:39 abubu dhclient: DHCPACK from 172.28.1.41
Mar 16 11:06:39 abubu dhclient: bound to 172.28.6.233 -- renewal in 33912 seconds.
Mar 16 11:06:46 keke dhcpd: DHCPDISCOVER from 00:14:5e:ce:66:14 via eth0
Mar 16 11:06:46 keke dhcpd: DHCPOFFER on 172.28.4.123 to 00:14:5e:ce:66:14 via eth0
Mar 16 11:06:54 keke dhcpd: DHCPREQUEST for 172.28.4.123 (172.28.1.41) from 00:14:5e:ce:66:14 via eth0
Mar 16 11:06:54 keke dhcpd: DHCPACK on 172.28.4.123 to 00:14:5e:ce:66:14 via eth0
Mar 16 11:06:54 keke atftpd[21175]: Serving /tftpboot/pxelinux.0 to 172.28.4.123:2070
Mar 16 11:06:54 keke atftpd[21175]: Serving /tftpboot/pxelinux.0 to 172.28.4.123:2071
Mar 16 11:06:54 keke atftpd[21175]: Serving /tftpboot/pxelinux.cfg/01-00-14-5e-ce-66-14 to 172.28.4.123:57089
Mar 16 11:06:54 keke atftpd[21175]: Serving /tftpboot/pxelinux.cfg/AC1C047B to 172.28.4.123:57090

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