VIM as an IDE for writing programs under Linux / UNIX

Posted on in Categories C Programming, Gentoo Linux, Howto, Linux, Tips, Ubuntu Linux, UNIX last updated October 12, 2007

I’m already using few tips described here. From the article:

So I like vim a lot, and I’ve been using it on and off for a few years, but recently I’ve been using it full-time to code in Python. I learned a few things along the way and I made vim a better IDE for myself. Here’s how.

You can follow along or go straight to author’s .vimrc file. Place the .vimrc file in your home folder and enjoy the goodies.

The first step is to make sure you have the equivalent power of jedit, textpad, gedit and the like.

Linux commands to help you navigate

Posted on in Categories CentOS, File system, Gentoo Linux, Howto, Linux, Linux desktop, Sys admin, Tips last updated December 2, 2007

As a Linux system administrator, you will need to find files in directories all over the file system. Especially those coming from a Windows background, often lost themselves while navigating file system.

Linux and other UNIX (BSD) OS offers an excellent collection of utilities, which can be use to finding the files and executables, remember you cannot memorize all the commands and files ;)
Commands to help you navigate:

  • file: Determines file types
  • which: Locates an executable in your PATH
  • whereis: Locates binaries and man page
  • find: Find the file
  • grep: Search for text/string in the named file name
  • strings: Find text string in a binary file

The which command

It is useful to locate a command. Some opertating system such as Solaris/HP-UX (even linux) have multiple homes. So you wanna find out which version you are going to use by order of the directories in your PATH variable. Try out following commands:
$ which ls
$ which vi
$ which vim

The file command

You would like to find out if a command is a shell script or a binary file or simply cannot recognize file by its extension then use file command to determine file type.
$ file /usr/sbin/useradd

/usr/sbin/useradd: ELF 32-bit LSB executable, Intel 80386, version 1 (SYSV), for GNU/Linux 2.2.0, dynamically linked (uses shared libs), stripped

Let us try another example:
# file /etc/shadow

/etc/shadow: ASCII text

But wait sec, you don’t have to type full command path:
$ file $(which adduser)

/usr/sbin/adduser: perl script text executable

The whereis command

It locates binaries and man pages. When you get message command not found then use whereis command to locate binary file. For example ifconfig command:
$ ifconfig

bash: ifconfig: command not found

Now locate ifconfig binary, enter:
$ whereis -b ifconfig

ifconfig: /sbin/ifconfig

So let us try the full path, enter:
$ /sbin/ifconfig

The grep command

The grep command can search for text or strings such as IP address, domain names and lots of other stuff inside a text file. Often new Linux sys admin forgets to configuration file names. However, you can use grep to find out those configuration file name. For example, find out the file containing IP address
# grep -R "" /etc/* | less

Find out kernel driver module bttv configuration file name, so that you can remove the driver:
# grep -R "bttv" /etc/* | less<

The strings Commands

The grep command is useful to search a text file, if you would like to find text string in a binary file then use strings command.
# strings /usr/bin/users

You might think this is stupid idea to search inside binary file for text string. Well, no it is not a stupid idea. For example, you would like to quickly find out if internet service supports tcpd access control facility via /etc/hosts.allow and /etc/hosts.deny files (read as tcp wrappers) or not. Let us find out if sshd server support tcpd or not:
# strings $(which sshd)| grep libwrap
libwrap refuse returns

The find Command

Use find command to find the files. Find all files belonging to the user charvi:
# find / -user charvi

Remove all core dump files
# find / -name core -exec rm -i{}\;

Please see more find command examples here and here. For more info please read the man pages of find, grep, file, which.

FreeBSD: Becoming Super User (su) or Enabling su Access For User Account

Posted on in Categories FreeBSD last updated May 7, 2012

The superuser is a privileged user with unrestricted access to all files and commands. The superuser has the special UID (user ID) 0. You need to become super user (root) only when tasks need root permissions. Here is how to become a super user:
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