Good free images hosting services on the Web?
Suggestions on some good free images hosting services on the Web? Two good free image hosting websites: Imgur: http://imgur.com/ Postimage.org: http://postimage.org/
How to force umount a NFS directory on Linux?
The NFS server is down. It is reported “Stale NFS file handle”. I tried ‘umount’ and ‘umount -f’. But neither succeeded. # umount /mnt/store umount.nfs: /mnt/store: Stale NFS file handle # umount -f /mnt/store umount.nfs: /mnt/store: Stale NFS file handle How to force umounting the NFS without rebooting the Linux server? I usually have to…
How to allow websites’ .htaccess files in Apache2?
How to allow websites to use .htaccess files in Apache2 web servers? The AllowOverride directive controls this: http://httpd.apache.org/docs/current/mod/core.html#allowoverride To allow AllowOverride in a directory, add the following rules to the /etc/httpd/conf/httpd.conf or similar configuration file for your apache installation: <Directory “/var/www/www.example.com”> Options FollowSymLinks # # AllowOverride controls what directives may be placed in .htaccess files….
How to host multiple websites on a Apache Linux web server?
I have a Linux web server with Apache (httpd). How to host multiple websites on Apache? To host websites www.example1.com and www.example2.com on a single node with Apache2 on a single IP, you can use VirtualHost as follows. Edit /etc/httpd/conf/httpd.conf and add the following lines: NameVirtualHost *:80 <VirtualHost *:80> DocumentRoot /var/www/example1.com ServerName www.example1.com # Other…
How to run firefox under different profiles simultaniusly?
Firefox has multiple profiles and I am aware of choosing them by invoking firefox with the -P option. But I find that after one firefox instance under one profile is running, even I choose another profile during starting with -P, the new instance is still running under the existing profile. How to run firefox with…
How to Add “nomodeset” to Grub2 in Fedora and Ubuntu
I need to add nomodeset to make my GPU card work on Linux. Latest Fedora and Ubuntu and their derives use grub2. How to add nomodeset permanently to grub2 on Fedora and Ubuntu? The parameters grub2 will use are stored in its grub.cfg file. The grub.cfg file is generated from grub’s default settings file /etc/default/grub….
How to redirect anything written on a file to another file in linux?
Suppose we have two files, a.txt and b.txt . If we write anything in a.txt & b.txt, it should be redirected to c.txt. tee may help for this purpose. tee: duplicate standard input You may try a command like this: echo “hello” | tee -a a.txt >>b.txt Both a.txt and b.txt will contain the “hello”….
How to wrap long lines in a text file on Linux?
I have some text files which contain some long lines. Now I would like to break lines to at most 80 characters. How to wrap long lines in a text file on Linux? The fold command can wrap lines. fold – wrap each input line to fit in specified width For your purpose, fold -w…
Block Ads in WordPress, while mobile view
Hi there, Quite recently I’ve created a native app (webview app)of my wordpress website and this wordpress site is using responsive theme as well. Now I want to publish this app at play store. The problem is that Adsense are not allowed to be shown in a native android app. So I want to know…
How to enable SSH service on Fedora Linux?
How to enable SSH service on Fedora Linux? By default, it seems ssh is not enabled. Fedora may not have sshd service installed/enabled by default. You will need to install and configure it by yourself. The following instructions is for Fedora 22 as an example. First, install the sshd server by # dnf install openssh-server…
How to change the display manager on Fedora Linux?
The default display manager on my Fedora 22 is gdm. If I would like to change it to other display manager like KDM, LightDM or other, which is the portable and reliable method? You can use the “system-switch-displaymanager” tools to manage the display manager. This is possibly the most portable way. To install it: #…
How to Passwordless SSH to an OpenWrt Router?
The good ssh-copy-id method which works well on common Linux seems not working for OpenWrt router. How to Passwordless SSH to an OpenWrt Router? OpenWrt’s SSH server is Dropbear. It can accept normal RSA keys. But the authorized_keys location is not the same as the openssh “~/.ssh/authorized_keys”. The location for the authorized_keys is /etc/dropbear/authorized_keys What…
How to merge 2 .a libraries to one .a library on Linux?
We have 2 static .a libraries and we would like to merge them into a single one for easier usage. How to merge 2 .a libraries to one .a library on Linux? With GNU ar, you can specify the single command-line option -M and control it with a script supplied via standard input, like the…
Windows 7 repetitively tried to update but failed every time I boot Windows 7
Windows 7 repetitively tried to update but failed every time I boot Windows 7. It will reboot automatically several times itself. How should I fix it? First, you need to identify which update causes the problem. You can find this in the Updates control panel tool as follows. After identifying the failed package (e.g. KB3033929…
How to configure systemd to boot Linux to console mode (runlevel 3)?
How to configure Linux (am using Fedora 21) managed by systemd to boot to console (init 3) mode? systemd has the concept of targets as a more flexible replacement for runlevels in sysvinit. Runlevel 3 is emulated by multi-user.target. runlevel3.target is a symbolic link to multi-user.target. You can switch to ‘runlevel 3’ by running #…
How to make Fedora Linux not clean some files in /tmp/?
On my Fedora 20, I find that the system automatically clean up file under /tmp/. This is convenient. However, it cause some problems for some programs. For example, HDFS puts its DataNode pid file under /tmp/ by default like hadoop-hadoop-datanode.pid. After it is cleaned up, the hadoop-daemon.sh script will consider there is no DataNode running….
How to deactivate a LVM logical volume on Linux?
How to deactivate a LVM logical volume activated by #vgchange -aay on Linux You may need to make a LVM volume group inactive and thus unknown to the kernel. To deactivate a volume group, use the -a (–activate) argument of the vgchange command. To deactivates the volume group vg, use this command # vgchange -a…
Xterm color codes for Vim on Linux
Vim uses Xterm color codes like 9, 1 and 114 on Linux. What’s the overall mapping from color to codes or codes to color? Xterm color table: You can also find the Xterm color codes here.
How to mount LVM volume from an external hard disk on CentOS?
On Fedora, after inserting/plugging in an exteranl hard disk with LVM partitions on it, the partitions will appear under /dev like /dev/lvm-group/lvm-partition. However, on CentOS 6, the LVM volumes do not appear automatically. How to mount LVM partitions from an external hard disk on CentOS? What you need on CentOS is to activate the LVM…
What’s wrong with the messages like “UnrecovData 10B8B BadCRC” and “failed command: READ FPDMA QUEUED” on Linux?
I keep seeing messages in dmesg as follows with “exception Emask 0x10” -> “SError: { UnrecovData 10B8B BadCRC }” -> “failed command: READ FPDMA QUEUED” -> “hard resetting link”: [ 7395.936692] ata4.00: exception Emask 0x10 SAct 0xe000 SErr 0x280100 action 0x6 frozen [ 7395.936701] ata4.00: irq_stat 0x08000000, interface fatal error [ 7395.936703] ata4: SError: {…