SD Card mounts read-only in Linux

The title might be misleading since my setup is using Linux Mint 18.3 but I have seen all kinds of posting related to this problem across Linux forums.  I have tried all kinds of remedies suggested online and it seems to be a hit or miss and cant seem to narrow it down.  Windows does not have any of these symptoms and can heal even should you forget to eject properly.

I have tried all the obvious ones such as changing permission on the filesystem to 777 and removing it as root or sudo.  I had one success with this method then it went back every time I eject the SD card, use it in a speaker player then try to access it again on the computer.

Tried the fsck and did work one time but I am very careful prior to removing the card by ejecting it [umount]. 

fsck -a /dev/sdb

Gparted didn't work.  But if I've continued to try, I think one of these days it would have worked.  Rebooted so many times that I felt like I was using Windows Vista.

The dd command didn't seem to work at all

dd if=/dev/zero of=/dev/sdb bs=1M count=10

I have noticed one time where my SD card had residual trash on the card .Trash-1000; however, nothing can remove it to include root.  Then found out that you have to delete the user's Trash then umount and remount.  This worked once then failed again.

rm -rf ~/.local/share/Trash/* 

A different scenario happened to where I plug in then eject then insert again then eventually it worked.  From Nemo file manager is whether or not I had the delete option which indicated that the SD card is now in read-write mode.

I have tried umounting then remount with rw options:

sudo fdisk -l
sudo mount -t vfat -o rw /dev/sdb1 /mnt

or

sudo mount -o remount,rw /dev/sdb1 /media/username/usbname

Finally I really think that by adding myself and the root into the disk group worked.

sudo usermod -G disk --append username
sudo usermod -G disk --append root

Bitnami Redmine Installation on Ubuntu 16.04

Bitnami Redmine Installation on Ubuntu 16.04

Using Bitnami Redmine, go to https://bitnami.com/stack/redmine to download the latest version of Redmine local installer for Linux.
Upload the binary to the server then run it as root

chmod +x bitnami-redmine-<version>-linux-x64-installer.run

./bitnami-redmine-<version>-linux-x64-installer.run

Made a symlink for easy access

ln -s /opt/redmine<version> /opt/redmine

Start/Stop Service




The native installer also includes a command-line script to start, stop and restart applications, named ctlscript.sh. This script can be found in the installation directory and accepts the options start, stop, restart, and status. To use it, log in to the server console and execute it following the examples below:


Call it without any service names to start all services:

Note: Only use sudo if the stack was installed as root
sudo installdir/ctlscript.sh start



Use it to restart a specific service only by passing the service name as argument - for example, mysql or apache:

Note: Only use sudo if the stack was installed as root
sudo installdir/ctlscript.sh restart mysql
sudo installdir/ctlscript.sh restart apache



Obtain current status of all services:
installdir/ctlscript.sh status




The list of available services varies depending on the required components for each application.

Email Fetching from Gmail

Install rake to provide /usr/bin/rake

sudo apt-get install rake

Crontab

*/2 5-22 * * * /opt/redmine/helpdeskEmailPoll.sh > /opt/redmine/helpdeskEmailPoll.log

File: /opt/redmine/helpdeskEmailPoll.sh

#!/bin/bash
source /opt/redmine/scripts/setenv.sh
cd /opt/redmine/apps/redmine/htdocs

RAILS_ENV="production" /usr/bin/rake redmine:email:receive_imap host=imap.gmail.com port=993 ssl=1 username=helpdesk@ssis.edu.vn password=h3lpdesk\! project=helpdesk unknown_user=create no_permission_check=1 no_account_notice=1

To check when the last time the cronjob to check the helpdesk email, go to /opt/redmine/helpdeskEmailPoll.log

Use a MySQL trigger to "fix" the Active Directory user auto-creation

A bit of a hack, but it gets the job done. Run this using the "/opt/redmine/mysql/bin/mysql -uroot -p" command line client:

delimiter //
CREATE TRIGGER `user_before_insert` BEFORE INSERT
ON `users`
FOR EACH ROW BEGIN
IF NEW.login like '%@ssis.edu.vn' THEN
SET NEW.login = replace(NEW.login,'@ssis.edu.vn','');
SET NEW.auth_source_id= (SELECT id from auth_sources where type="AuthSourceLdap" and name like "SSIS%" limit 1);
END IF;
END//

CREATE TRIGGER `user_before_update` BEFORE UPDATE
ON `users`
FOR EACH ROW BEGIN
IF NEW.login like '%@ssis.edu.vn' THEN
SET NEW.login = replace(NEW.login,'@ssis.edu.vn','');
SET NEW.auth_source_id= (SELECT id from auth_sources where type="AuthSourceLdap" and name like "SSIS%" limit 1);
END IF;
END//

CREATE TRIGGER `user_after_insert` AFTER INSERT
ON `users`
FOR EACH ROW BEGIN
IF NEW.auth_source_id='1' THEN
SET @groupid := (SELECT DISTINCT id from users where type="Group" and lastname="SSIS Users");
INSERT INTO groups_users (group_id, user_id) VALUES (@groupid, NEW.id);
END IF;
END//

delimiter ;

Accessing PhpMyAdmin On Linux And Mac OS X

To access the application using your Web browser, create an SSH tunnel, as described below.

• Open a new terminal window on your local system (for example, using "Finder -> Applications -> Utilities -> Terminal" in Mac OS X or the Dash in Ubuntu).
• You have two options to configure the SSH tunnel: connect to the server using a private key (recommended) or connect to the server using a SSH password. Follow the instructions below per each option:
  • Option 1: Connect to the server using a private key
    • Make sure that you have your SSH credentials (.pem key file) in hand.
    • Run the following command to configure the SSH tunnel. Remember to replace KEYFILE with the path to your private key and SERVER-IP with the public IP address or hostname of your server:

      ssh -N -L 8888:127.0.0.1:80 -i KEYFILE syad@srvr-uredmine.ssis.edu.vn
      

  • Option 2: Connect to the server using a SSH password
    • Run the following command, remembering to replace SERVER-IP with the public IP address or hostname of your server. Enter your SSH password when prompted.

      ssh -N -L 443:127.0.0.1:443 sysad@srvr-uredmine.ssis.edu.vn
      

NOTE: If successful, the above commands will create an SSH tunnel but will not display any output on the server console.

• Access the phpMyAdmin console through the secure SSH tunnel you created, by browsing to https://127.0.0.1/phpmyadmin.
• Log in to phpMyAdmin by using the following credentials:
  • Username: root
  • Password: application password

File Attachments

Every year, Redmine will create a new directory under /opt/redmine/apps/redmine/htdocs/files/<year> with the permission ownership of root.root.  We need to change it to daemon.daemon in order for our users to upload new files.  We need to keep in mind to perform this every year or write a cronjob to perform this task.

Redirect multiple domain with NGINX

Web server

(web.example.com):  /etc/nginx/sites-available/redirect

server {
listen 80;
server_name records.example.com summer.example.com helpdesk.example.com;
if ($host = 'records.example.com'){
return 301 http://docs.google.com/;
}
if ($host = 'summer.example.com'){
return 301 http://domainsomewhere.net;
}
if ($host = 'helpdesk.example.com'){
return 301 http://youtube.com/sdfasa;
}
}

ln -s /etc/nginx/sites-available/redirect /etc/nginx/sites-enabled/redirect
nginx -t
service nginx restart

DNS

DNS entry point to webserver (ie. records alias to web.example.com)

Check website page load and trace route

Here are two very nice website page load check and trace route.  It also provide recommendations on how to improve the page's performance.

http://www.monitis.com/pageload/
https://tools.pingdom.com

Output Result from df Command STDOUT to HTML

An example of where we need this is to display the output from the command df to a webpage. All the spaces and newline are all disregarded by HTML so it will display as one long line.

PRE Block in HTML

Solution: Wrap output such as this in a pre block in HTML.

STORAGE=$(df -PTh | column -t | sort -n -k6n)
echo "<pre>$STORAGE</pre>"

Though, HTML does not take care of preserving white space

To preserve the white space

In the output of the command chain is white space in the form of spaces and newlines (and you are lucky there are no tabs). You should make pipe the output into | sed 's/ /&nbsp;/g' | sed 's/^/<br>/':

STORAGE=$(df -PTh | column -t | sort -n -k6n)| sed 's/ /&nbsp;/g' | sed 's/^/<br>/'

to preserve whitespace. You can use that without getting the font changing effect that <pre>induces.

HTML Table Format

$ printf "<pre>%s</pre>\n" "$storage" >> file.html 
There should be no need to include column. This is a candidate for a HTML table, and could be begotten by something like:df -PTh | \

sed '1d' | \
sort -n -k6 | \
awk '
{
 printf "\n\t<tr>";
 for (n = 1; n < 7; ++n)
   printf("\n\t<td>%s</td>",$n);
   printf "\n\t<td>";
 for(;n <= NF; ++n)
   printf("%s ",$n);
   printf "</td>\n\t</tr>"
}
'
Wrap it in something like:

<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Disk space usage</title>
<style>
table, td, th {
  border : 1px solid green;
}
th {
  background-color: green;
  color : white;
}
</style>
</head><body>
<table>
  <tr>
    <th>Filesystem</th>
    <th>Type</th>
    <th>Size</th>
    <th>Used</th>
    <th>Avail</th>
    <th>Use%</th>
    <th>Mounted on</th>
  </tr>
  <!-- df output awk table -->
  <?php include('file.html'); ?>
</table>
</body>
</html>