CentOS and Red Hat comes with vim-minimal installed by default which lacks support for syntax highlighting and many other features.

To see currently installed version, run vi --version at the command line and note the list of enabled and disabled features.

[root@centos ~]# vi --version
VIM - Vi IMproved 7.4 (2013 Aug 10, compiled Aug  2 2017 00:45:54)
Included patches: 1-160
Modified by <[email protected]>
Compiled by <[email protected]>
Small version without GUI.  Features included (+) or not (-):
+acl             -farsi           -mouse_sgr       -tag_old_static
-arabic          -file_in_path    -mouse_sysmouse  -tag_any_white
-autocmd         -find_in_path    -mouse_urxvt     -tcl
-balloon_eval    -float           -mouse_xterm     +terminfo
-browse          -folding         +multi_byte      -termresponse
+builtin_terms   -footer          -multi_lang      -textobjects
-byte_offset     +fork()          -mzscheme        -title
-cindent         -gettext         -netbeans_intg   -toolbar
-clientserver    -hangul_input    -path_extra      -user_commands
-clipboard       +iconv           -perl            -vertsplit
-cmdline_compl   -insert_expand   -persistent_undo -virtualedit
+cmdline_hist    +jumplist        -printer         +visual
-cmdline_info    -keymap          -profile         -visualextra
-comments        -langmap         -python          -viminfo
-conceal         -libcall         -python3         -vreplace
-cryptv          -linebreak       -quickfix        +wildignore
-cscope          -lispindent      -reltime         -wildmenu
-cursorbind      -listcmds        -rightleft       +windows
-cursorshape     -localmap        -ruby            +writebackup
-dialog          -lua             -scrollbind      -X11
-diff            -menu            -signs           -xfontset
-digraphs        -mksession       -smartindent     -xim
-dnd             -modify_fname    -sniff           -xsmp
-ebcdic          -mouse           -startuptime     -xterm_clipboard
-emacs_tags      -mouse_dec       -statusline      -xterm_save
-eval            -mouse_gpm       -sun_workshop    -xpm
-ex_extra        -mouse_jsbterm   -syntax
-extra_search    -mouse_netterm   -tag_binary
   system vimrc file: "/etc/virc"
     user vimrc file: "$HOME/.vimrc"
 2nd user vimrc file: "~/.vim/vimrc"
      user exrc file: "$HOME/.exrc"
  fall-back for $VIM: "/etc"
 f-b for $VIMRUNTIME: "/usr/share/vim/vim74"
Compilation: gcc -c -I. -Iproto -DHAVE_CONFIG_H     -O2 -g -pipe -Wall -fexceptions -fstack-protector-strong --param=ssp-buffer-size=4 -grecord-gcc-switches   -m64 -mtune=generic -D_GNU_SOURCE -D_FILE_OFFSET_BITS=64 -U_FORTIFY_SOURCE -D_FORTIFY_SOURCE=1
Linking: gcc   -Wl,-z,relro  -L/usr/local/lib -Wl,--as-needed -o vim        -lm  -lselinux -lncurses -lacl -lattr -ldl

To use the version of vim with most of the features enabled in CentOS / Red Hat, you’ll have to install vim-enhanced. This could be done by following these steps at the command line;

1. Remove the installed vim-minimal.

   yum remove -y vim-minimal

2. Update package list from the repositories.

   yum -y update

3. Install vim-enhanced and related dependencies.

   yum install -y vim-enhanced

Running vim --version should produce a more desirable output.

[root@centos ~]# vim --version
VIM - Vi IMproved 7.4 (2013 Aug 10, compiled Aug  2 2017 00:45:39)
Included patches: 1-160
Modified by <[email protected]>
Compiled by <[email protected]>
Huge version without GUI.  Features included (+) or not (-):
+acl             +farsi           +mouse_netterm   +syntax
+arabic          +file_in_path    +mouse_sgr       +tag_binary
+autocmd         +find_in_path    -mouse_sysmouse  +tag_old_static
-balloon_eval    +float           +mouse_urxvt     -tag_any_white
-browse          +folding         +mouse_xterm     -tcl
++builtin_terms  -footer          +multi_byte      +terminfo
+byte_offset     +fork()          +multi_lang      +termresponse
+cindent         +gettext         -mzscheme        +textobjects
-clientserver    -hangul_input    +netbeans_intg   +title
-clipboard       +iconv           +path_extra      -toolbar
+cmdline_compl   +insert_expand   +perl            +user_commands
+cmdline_hist    +jumplist        +persistent_undo +vertsplit
+cmdline_info    +keymap          +postscript      +virtualedit
+comments        +langmap         +printer         +visual
+conceal         +libcall         +profile         +visualextra
+cryptv          +linebreak       +python/dyn      +viminfo
+cscope          +lispindent      -python3         +vreplace
+cursorbind      +listcmds        +quickfix        +wildignore
+cursorshape     +localmap        +reltime         +wildmenu
+dialog_con      -lua             +rightleft       +windows
+diff            +menu            +ruby/dyn        +writebackup
+digraphs        +mksession       +scrollbind      -X11
-dnd             +modify_fname    +signs           -xfontset
-ebcdic          +mouse           +smartindent     -xim
+emacs_tags      -mouseshape      -sniff           -xsmp
+eval            +mouse_dec       +startuptime     -xterm_clipboard
+ex_extra        +mouse_gpm       +statusline      -xterm_save
+extra_search    -mouse_jsbterm   -sun_workshop    -xpm
   system vimrc file: "/etc/vimrc"
     user vimrc file: "$HOME/.vimrc"
 2nd user vimrc file: "~/.vim/vimrc"
      user exrc file: "$HOME/.exrc"
  fall-back for $VIM: "/etc"
 f-b for $VIMRUNTIME: "/usr/share/vim/vim74"
Compilation: gcc -c -I. -Iproto -DHAVE_CONFIG_H     -O2 -g -pipe -Wall -fexceptions -fstack-protector-strong --param=ssp-buffer-size=4 -grecord-gcc-switches   -m64 -mtune=generic -D_GNU_SOURCE -D_FILE_OFFSET_BITS=64 -U_FORTIFY_SOURCE -D_FORTIFY_SOURCE=1
Linking: gcc   -L. -Wl,-z,relro -fstack-protector -rdynamic -Wl,-export-dynamic -Wl,--enable-new-dtags -Wl,-rpath,/usr/lib64/perl5/CORE  -Wl,-z,relro  -L/usr/local/lib -Wl,--as-needed -o vim        -lm -lnsl  -lselinux  -lncurses -lacl -lattr -lgpm -ldl   -Wl,--enable-new-dtags -Wl,-rpath,/usr/lib64/perl5/CORE  -fstack-protector  -L/usr/lib64/perl5/CORE -lperl -lresolv -lnsl -ldl -lm -lcrypt -lutil -lpthread -lc

The command used to list directory content in Linux is ls. With the -R option, ls will traverse the directory recursively, showing the content of the particular directory and all its subdirectories. Relative directory path is displayed before the directory content is actually listed.

The following is an example of the command in use;

$ ls -R testdir/
testdir/:
subdir1  subdir2

testdir/subdir1:
subsubdir1  subsubdir2

testdir/subdir1/subsubdir1:
file1

testdir/subdir1/subsubdir2:
file2

testdir/subdir2:
subsubdir1  subsubdir2

testdir/subdir2/subsubdir1:
file3

testdir/subdir2/subsubdir2:
file4

Huawei E1552 is a HSDPA USB Stick capable of delivering HSDPA connectivity at up to 3.6Mbps. Being a USB stick cum modem cause some problem with Ubuntu (and Linux general), but is easily fixable by the following method.

sudo is a program that allows a user to run programs with the security privileges of another user. If no user is specified, it will try to run the other program as root, or the superuser. By default, running sudo will prompt for the superuser password, as in the following example;

shakir@anduril:~$ sudo vi /etc/resolv.conf

 We assume you have received the usual lecture from the local System
 Administrator. It usually boils down to these three things:

 #1) Respect the privacy of others.
 #2) Think before you type.
 #3) With great power comes great responsibility.

 Password:

While this is good for security reason, normal users would want to avoid the password prompt completely, especially if they are just running it on a desktop.

To enable passwordless sudo, one need to edit the /etc/sudoers file. This can be done by directly editing the file using your favorite editor as the following;

$ sudo vi /etc/sudoers

or by using a dedicated program just for this by issuing the following command;

$ su -
# visudo

In editing the file, there are 2 options to enable passwordless sudo, which is to allow by group, or by user.

To everyone in the group mygroup to be able to use sudo without password, add the following line;

%mygroup ALL=NOPASSWD: ALL

Adding the following line will allow the user shakir to use sudo without password

shakir ALL=NOPASSWD: ALL

From it’s man page, rsync is a program that behaves in much the same way that rcp does, but has many more options and uses the rsync remote-update protocol to greatly speed up file transfers when the destination file is being updated.

The rsync remote-update protocol allows rsync to transfer just the differences between two sets of files across the network connection, using an efficient checksum-search algorithm described in the technical report that accompanies this package.

Say 192.168.1.10 (anduril) is the backup destination , herugrim is the host’s hostname, the following step will automatically rsync the home directory to the backup server.

7-Zip is a file archiver program that claims to compress files into smaller size compared to other programs such as WinRAR and WinZip. The program can pack and unpack various formats such as ZIP, GZIP, BZIP2, TAR, and of course, its own format, 7z. The 7z format itself is actually a container that supports few compression method such as LZMA, Deflate and BZIP2, with LZMA as default.

The program to view and change a machine’s hostname in Linux is a program named hostname itself. In a machine’s with the hostname test, running the program will produce the following:

$ hostname
test

After installing Ubuntu and its derivatives on a Dell XPS Studio, the headphone jacks are both unusable. Plugging in earphone to the jack produces no sound, and the system still output the sound on the laptop’s speaker.

The problem is related to alsa. To fix it, follow these steps.