The LaTex packages in CentOS 7 Linux is not sufficient enough. I would like to Install Tex Live such as Tex Live 2016. How could I install it on CentOS 7? The best way I found is to use the texlive offical installation tool to install the full packages for texlive 2016. It will take
Read more
How to install dia on CentOS 7 Linux?
Posted onDia seems not available in the official repository of CentOS 7. How to install dia on CentOS 7 Linux? You can find built dia packages in some additional repositories for CentOS. First, enable EPEL following this link. Second, enable Nux Desktop following this link. Then, you can install dia by # yum install dia
What’s the difference between memory coherence and consistency?
Posted onIn memory hierarchical, it needs to be coherence and consistency. However, they are different things. What are the differences? Memory coherence: a memory system is coherent if any read of a data item returns the most recently written value of that data item (what values can be returned by a read). Memory consistency: A memory
Read more
encfs on CentOS 6 can’t mount as normal user
Posted onOn CentOS 7, using a normal user, encfs works just well. On CentOS 6, using the root user, encfs works. However, the problem is, on CentOS 6, using a normal user account, encfs does not work as on CentOS 7. $ encfs -s ~/t/.enc ~/t/enc EncFS Password: fuse: failed to exec fusermount: Permission denied fuse
Read more
How to remove the bottom panel in gnome 3 classic?
Posted onThe gnome 3 classic’s bottom panel looks not useful to me. I do not use it. How to remove the bottom panel in gnome 3 classic? That bottom panel is from the “Window List” plugin. The gnome 3 classic package depends on that plugin package on CentOS 7 as far as I checked. And Gnome
Read more
Ubuntu’s GUI response is very slow
Posted onFor Dell PowerEdge T630 server, if you install latest Ubuntu desktop version (16.04) or (14.04), you will get a very slow GUI (X-window). $ inxi -G Graphics: Card: Matrox Systems G200eR2 X.org: 1.15.1 driver: vesa tty size: 205×58 Advanced Data: N/A out of X For Ubuntu 14.04.1, this problem can be solved by following steps.
Read more
In Bash script, how to join multiple lines from a file?
Posted onIn Bash script, how to join multiple lines from a file? For example, to join the lines a good boy to a good boy You can use tr command, something like: tr -s ‘n’ ‘ ‘ < file.txt It just goes through its input and makes changes according to what you specify in two sets
Read more
How to save the output of screen windows to a file on Linux?
Posted onIn the screen, copying the history of the window output is quite hard. How to save the screen easily to a file? First type Ctrl + A then : to get to command mode. In the command mode, execute hardcopy -h /path/to/file screen will save the window output to /path/to/file.
How to make output jpeg file of xsane smaller on Linux?
Posted onxsane’s output jpeg file is large (10+MB). But we usually do not need it to make a so big jpeg file. Some compression (even lossy) will be good. How to make output jpeg file of xsane smaller on Linux? You can adjust the output file size by changing the compression levels and quality. Through the
Read more
How to redirect non-www domain to www domain in .htaccess?
Posted onI have a website. But I would like use the www.example.com instead of example.com. How to redirect non-www domain to www domain on my server? I am using apache2 (httpd). You can add a piece of code into the top .htaccess in your site: Specific method: redirect example.com domain to www.example.com domain RewriteEngine On RewriteBase
Read more
How to make tee catch the stderr only in Linux?
Posted onI would like to make tee catch the stderr and log it into a file. A brute force method by let tee listen on both stderr and stdout is okay like cmd 2>&1 | tee -a log But how to make tee catch the stderr only? You can make use of “process substitution” (>(…)) to
Read more
How to set up HP printer and scaner on CentOS 7?
Posted onHow to set up the driver for an HP all-in-one printer/scanner on CentOS 7 Linux? First, install these packages and it may ask you to download and install other plugins. Without these packages, my printer does work. # yum install hplip hplip-gui hpijs Second, install plugins for the HP printer. # hp-plugin Then you can
Read more
How to detect whether a file is readable and writable in Python?
Posted onBefore reading or writing a file, access should be checked first. How to detect whether a file is readable and writable in Python? You can use the os.access(path, mode) library function https://docs.python.org/release/2.6.6/library/os.html#os.access like the Linux access library function for C. It returns True if access is allowed, False if not. For readable and writable, you
Read more
In Python, how to check whether a key already exists in a dict?
Posted onHow to check whether a key already exists in a dict in Python since version 2.6? If d is a dict(), you can directly test whether a key k is in d in Python by the in keyword like if k in d: ..
How to make a unique temporary file in Bash on Linux?
Posted onIt is common to make a unique temporary file. How to make a unique temporary file in Bash on Linux safely and quickly? You can use the mktemp program. In the simplest way, tmpfile=$(mktemp) The file will be like /tmp/tmp.j0wD39Mr3b if you do not prefer any meaningful names. You can set the file to your
Read more
How to handle spaces in paths with rsync on Linux?
Posted onThe common rsync commands seems not handle spaces well. For example, rsync -avxP file “user@server:/data/my dir” It reports: rsync: link_stat “/home/zma/file” failed: No such file or directory (2) How to make rsync handle spaces well? You can use the –protect-args option of rsync. $ rsync –protect-args -avxP file “user@server:/data/my dir” What does –protect-args do: -s,
Read more
How to install curlftpfs on CentOS 7?
Posted oncurtlftpfs is a nice tool to mount ftp to local. How to install curlftpfs on CentOS 7? The software package for curlftpfs is proved in EPEL. To install curlftpfs, first, enable EPEL following instructions here. Then, install curlftpfs by # yum install curlftpfs
How tinstall aria2 on CentOS 7?
Posted onHow tinstall aria2 on CentOS 7? aria2 is a great tool for downloading files from the Internet. The software package for aria2 is proved in EPEL. To install aria2, first, enable EPEL following instructions here. Then, install aria2 by # yum install aira2
How to collect VM exit numbers in KVM
Posted onSometimes, we may want to know the specific benchmark can cause what kind of VM exits. 1, Install perf. 2, # perf kvm stat record -a ^C 3, # perf kvm stat report This will report your VM exit numbers and what kind of operation lead to VM exit. You may need to compare many
Read more
How to install sshfs on CentOS 7?
Posted onsshfs is a nice tool. But it seems there is no support to it in a newly installed CentOS 7 Linux system: Not installed by default: # sshfs -bash: sshfs: command not found Seems not available from the repositories # yum install sshfs -y Loaded plugins: fastestmirror Repodata is over 2 weeks old. Install yum-cron?
Read more