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.
SysTutorials Posts
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: {…
mkfs refuses to make filesystem with message “is apparently in use by the system; will not make a filesystem here!”
I have a disk from another server installed on a new server. However, when I try to make a filesystem on it, mkfs reports # mkfs -t ext4 /dev/sdd1 mke2fs 1.42.8 (20-Jun-2013) /dev/sdd1 is apparently in use by the system; will not make a filesystem here! This is a new disk to the new server….
How to make curl request pass the Squid proxy?
I use curl to send requests to remote servers like following command. curl http://example.com/send –date-urlencode “data=hello” However, it is blocked by the network proxy squid in some networks with message like (some info anonymized with “…”): ERROR The requested URL could not be retrieved POST /… HTTP/1.1 Proxy-Authorization: Basic … User-Agent: Mozilla/4.0 (compatible;) Host: ……
How to run screen on a Linux host reporting “Cannot make directory ‘/var/run/screen’: Permission denied”?
I want to run screen on a remote host on which I do not have root/sudo privilege and screen is not installed. I can compile or copy the screen program that can run on the host. However, it reports: “Cannot make directory ‘/var/run/screen’: Permission denied” As screen is not installed on the host, the directory…
How to encode spaces in curl GET request URL on Linux?
The problem is like this: I would like to send a GET request using curl and the content has spaces, such as curl “http://example.com/send?msg=hello world” The space and the “world” will be left away if this command is executed directory on Linux. How to encode spaces in curl request URL? You can use the –date-urlencode…
How to handle missing blocks and blocks with corrupt replicas in HDFS?
One of HDFS cluster’s hdfs dfsadmin -report reports: Under replicated blocks: 139016 Blocks with corrupt replicas: 9 Missing blocks: 0 The “Under replicated blocks” can be re-replicated automatically after some time. How to handle the missing blocks and blocks with corrupt replicas in HDFS? Understanding these blocks A block is “with corrupt replicas” in HDFS…
how to install older version gcc/g++ in Ubuntu (other linux distro are similar)
When we compile some project, it needs older version gcc/g++ version. So how to insall older ones in ubuntu 16? Install older gcc/g++ version sudo apt-get install gcc-4.4 g++-4.4 g++-4.4-multilib gcc-4.4-multilib Set gcc/g++ version to be used automatically sudo update-alternatives –install /usr/bin/gcc gcc /usr/bin/gcc-4.4 50 sudo update-alternatives –install /usr/bin/g++ gcc /usr/bin/g++-4.4 50 You may need…
How to identify a certificated lightning cable for iPhone 6?
There are various lightning cables on the market. I ever purchased one but it does not work for iPhone 6… How to identify a certificated lightning cable that is good for iPhone 6? (I know the cables from Apple will definitely work. But it takes time to receive one from Apple or not always easy…
How to make AdSense responsive ads show rectangle ads instead of horizontal ones?
I noticed that many sites with AdSense responsive ads show large rectangle ads (336px x 280px) or large rectangle text ads (full width x 280px). However, in my own website (640px width content area), it shows most of time horizontal ones. How to make AdSense responsive ads show rectangle ads instead of horizontal ones? At…
How to find a wireless network adapter’s speed in Linux?
How to find a wireless adapter‘s speed in Linux? ethtool does not show the speed of the wireless adapters. For finding the configured speed of wireless adpaters in Linux, you can use the iwconfig tool. iwconfig: configure a wireless network interface For example, to find the speed of the wireless adapter wlp8s0: # iwconfig wlp8s0…
How to find a network adapter’s speed in Linux?
I have a Linux box and it is connected to a network through a network adapter, say gate. How to find what is the current speed (10Mbps, 100Mbps or 1000Mbps) of the adapter? You can find the network adapter speed by the ethtool command: ethtool: query or control network driver and hardware settings For example,…
How to disable SSH reverse DNS lookup on Linux?
How to disable the reverse DNS lookup by the SSD server on Linux? To turn off reverse DNS lookups of the SSH daemon, log on the server and add UseDNS no to /etc/ssh/sshd_config. And remember to restart the sshd service by service sshd restart or systemctl restart sshd.service or other commands depending on your system.
Implementation of strstr in glibc
What is the implementation of strstr in glibc? Implementation of STRSTR in glibc (string/strstr.c): /* Return the first occurrence of NEEDLE in HAYSTACK. Return HAYSTACK if NEEDLE is empty, otherwise NULL if NEEDLE is not found in HAYSTACK. */ char * STRSTR (const char *haystack_start, const char *needle_start) { const char *haystack = haystack_start; const…
Printing “powernow-k8 transition frequency failed” after install XEN
After I installed XEN hypervisor, the tty0 (CTRL+ALT+F1) prints “powernow-k8 transition frequency failed” to STDOUT continously, how to solve it? sudo rmmod powernow_k8 From https://lists.debian.org/debian-user/2013/01/msg00754.html How to make the settings persistent (take effect after reboot)? 1, Create script file ‘/etc/init.d/stop_pwoerk8.sh’ as follows. harry2vera@node1:/etc/init.d$ cat stop_pwoerk8.sh #! /bin/sh rmmod powernow_k8 2, Add the full PATH of…
rtnetlink answers file exists
When you replace dynamic IP to static IP, you may need to restart your netwrok on Debian as follows. $sudo /etc/init.d/networking restart … …. reconfiguring network interfaces…rtnetlink answers file exists … However, error happens here “rtnetlink answers file exists”. How to solve it??? Run following commands could solve this problem # ip addr flush dev…
Max number of Emails allowed to Sent from Gmail SMTP per day
Gmail’s SMTP is convenient. You “sender” needs not to be always your Gmail address (but the emails will include your Gmail address in the header “send by”). I am wondering how many emails at maximum can I send each day through Gmail’s SMTP. Here there a nice recent list of the sending limits of the…
I cannot login Ubuntu Precise desktop
I cannot login desktop in Ubuntu Precise. It told me following errors: Could not write bytes: Broken Pipe… Check Battery Satte Actually, I tried many ways to solve this problem. It seems that something wrong with my lightdm software so, at last, I use gdm software to replace lightdm to kill this problem. Just install…
How to exclude last N columns in Bash on Linux?
How to exclude last N columns of a string in bash? The point is that the number of columns in each line is uncertain (but > N). For example, I would like to remove the last 2 columns separated by ‘.’ in the following lines. systemd.3.gz systemd.mount.3.gz systemd.mount.f.3.gz The simple cut command cut -d’.’ -f1…