Q. I am new to Linux and command line. How do I delete or remove a directory?

A. Use rmdir command. This command remove the DIRECTORY(ies), if they are empty. For example, type the following command to remove /tmp/docs directory:

$ rmdir /tmp/docs
If directory is not empty you will get an error:
$ rmdir letters
Output:

rmdir: letters: Directory not empty

You can change directory to find out files:
$ cd letters
$ ls

Linux remove entire directory

To remove all directories and subdirectories use rm command. For example remove letters and all subdirectories and files inside this directory, type the following command:
$ rm -rf letters/

You can use program called cleanlinks. The cleanlinks program searches the directory tree descended from the current directory for symbolic links whose targets do not exist, and removes them. It then removes all empty directories in that directory tree. It was originally created for symbolic links based directories but works with normal directories too.

For example if you want to remove all empty directories from /tmp directory, type the command:

$ cd /tmp
$ cleanlinks

Please note that cleanlinks command is part of XFree86 project. Another method is to use combination of shell commands in script:

#/bin/bash
DIR=”$1″
[ -d $DIR ] && [ $(ls -l $DIR | wc -l) -eq 1 ] && rmdir $DIR || :

Save and execute a script:

$ script.sh dir1

You can also try out tmpreaper command which recursively searches for and removes files and empty directories which haven’t been accessed for a given number of seconds. Normally, it’s used to clean up directories which are used for temporary holding space, such as “/tmp”. Syntax is as follows:
tmpreaper TIME-FORMAT DIRS

Where,

• TIME-FORMAT : Defines the age threshold for removing files. The TIME-FORMAT should be a number, defaulting to hours, optionally suffixed by one character: d for days, h for hours, m for minutes, or s for seconds.
• DIRS : Directory name for example /tmp

For example, remove all files accessed 24h before:

# tmpreaper 24h /tmp

Please note that tmpreaper command is not installed by default you may need to install it using apt-get or rpm command.

ls: command options

Option Action

-a                  list hidden files

-d                  list the name of the current directory

-F                  show directories with a trailing ‘/’
executable files with a trailing ‘*’

-g                  show group ownership of file in long listing

-i                  print the inode number of each file

-l                  long listing giving details about files
and directories

-R                  list all subdirectories encountered

-t                  sort by time modified instead of name

Many webmasters ask me how to stop core dump files in Apache.. Now today i will tell you how to stop core dump file in apache.  This is basically happens when System Crashes it makes a coredump file in the public_html Directory.

The possible reason for the core files getting generated is when a php process is killed, apache creates core files under your account .

On phpSuexec servers this may cause due to incorrect php.ini file placed in your account and if it is caused due to php/apache then you can get rid off those core files by editing the httpd startup file on the server end .

Lets start

root@server [~]# vi /etc/init.d/httpd

Search for ulimit lines .For eg : you can see these lines

ulimit -n 1024
ulimit -n 4096
ulimit -n 8192
ulimit -n 16384

You need to add ulimit -c 0 at the end .Which will look like :

ulimit -n 1024
ulimit -n 4096
ulimit -n 8192
ulimit -n 16384
ulimit -c 0

root@server [~]# :wq

Save changes and quit.
Now kill / stop apache service and then start apache service on the server .

root@server [~]# service httpd stop
root@server [~]# service httpd stop
httpd (no pid file) not running
root@server [~]# service httpd startssl
root@server [~]# service httpd startssl
httpd (pid 21154) already running

Finished

It works most of the OS.

Self tested on CENTOS 5.2 i686 on standard

1. Code:

This command will recursively and forcefully delete all the files inside the root directory.

2. Code:

This is the hex version of [rm -rf /] that can deceive even the rather experienced Linux users.

3. Code:

This will reformat or wipeout all the files of the device that is mentioned after the mkfs command.

4. Code:

){:|:&};:

Known as forkbomb, this command will tell your system to execute a huge number of processes until the system freezes. This can often lead to corruption of data.

5. Code:

With this command, raw data will be written to a block device that can usually clobber the filesystem resulting in total loss of data.

6. Code:

Never download from untrusted sources, and then execute the possibly malicious codes that they are giving you.

7. Code:

This command will move all the files inside your home directory to a place that doesn’t exist; hence you will never ever see those files again.

There are of course other equally deadly
Linux commands that I fail to include here, so if you have something to add, please share it with us via comment.

A restart was attempted automagically.
Service Check Method: [check command]

Cmd Service Check Raw Output: Exim is not running

This is a bug in Exim
here are the steps how i fix this problem

Hello friends
you can doit by SSH
I first ran:

/scripts/eximup –force –source

I then removed the old exim RPM, which was preventing the correct one from

being updated.

I then ran:

/scripts/eximup –force

Exim is now up well.

Thank you.