Wednesday, May 28, 2014

12 Useful “df” Commands to Check Disk Space in Linux

On the internet you will find plenty of tools for checking disk space utilization in Linux. However, Linux has a strong built in utility called ‘df‘. The ‘df‘ command stand for “disk filesystem“, it is used to get full summary of available and used disk space usage of file system on Linux system.
Using ‘-h‘ parameter with (df -h) will shows the file system disk space statistics in “human readable” format, means it gives the details in bytes, mega bytes and gigabyte.
How to Check Disk Space in Linux
Useful df Command Examples
This article explain a way to get the full information of Linux disk space usage with the help of ‘df‘ command with their practical examples. So, you could better understand the usage of df command in Linux.

1. Check File System Disk Space Usage

The “df” command displays the information of device name, total blocks, total disk space, used disk space, available disk space and mount points on a file system.
[root@tecmint ~]# df

Filesystem           1K-blocks      Used Available Use% Mounted on
/dev/cciss/c0d0p2     78361192  23185840  51130588  32% /
/dev/cciss/c0d0p5     24797380  22273432   1243972  95% /home
/dev/cciss/c0d0p3     29753588  25503792   2713984  91% /data
/dev/cciss/c0d0p1       295561     21531    258770   8% /boot
tmpfs                   257476         0    257476   0% /dev/shm

2. Display Information of all File System Disk Space Usage

The same as above, but it also displays information of dummy file systems along with all the file system disk usage and their memory utilization.
[root@tecmint ~]# df -a

Filesystem           1K-blocks      Used Available Use% Mounted on
/dev/cciss/c0d0p2     78361192  23186116  51130312  32% /
proc                         0         0         0   -  /proc
sysfs                        0         0         0   -  /sys
devpts                       0         0         0   -  /dev/pts
/dev/cciss/c0d0p5     24797380  22273432   1243972  95% /home
/dev/cciss/c0d0p3     29753588  25503792   2713984  91% /data
/dev/cciss/c0d0p1       295561     21531    258770   8% /boot
tmpfs                   257476         0    257476   0% /dev/shm
none                         0         0         0   -  /proc/sys/fs/binfmt_misc
sunrpc                       0         0         0   -  /var/lib/nfs/rpc_pipefs

3. Show Disk Space Usage in Human Readable Format

Have you noticed that above commands displays information in bytes, which is not readable yet all, because we are in a habit of reading the sizes in megabytes, gigabytes etc. as it makes very easy to understand and remember.
The df command provides an option to display sizes in Human Readable formats by using ‘-h’ (prints the results in human readable format (e.g., 1K 2M 3G)).
[root@tecmint ~]# df -h

Filesystem            Size  Used Avail Use% Mounted on
/dev/cciss/c0d0p2      75G   23G   49G  32% /
/dev/cciss/c0d0p5      24G   22G  1.2G  95% /home
/dev/cciss/c0d0p3      29G   25G  2.6G  91% /data
/dev/cciss/c0d0p1     289M   22M  253M   8% /boot
tmpfs                 252M     0  252M   0% /dev/shm

4. Display Information of /home File System

To see the information of only device /home file system in human readable format use the following command.
[root@tecmint ~]# df -hT /home

Filesystem  Type    Size  Used Avail Use% Mounted on
/dev/cciss/c0d0p5 ext3     24G   22G  1.2G  95% /home

5. Display Information of File System in Bytes

To display all file system information and usage in 1024-byte blocks, use the option ‘-k‘ (e.g. –block-size=1K) as follows.
[root@tecmint ~]# df -k

Filesystem           1K-blocks      Used Available Use% Mounted on
/dev/cciss/c0d0p2     78361192  23187212  51129216  32% /
/dev/cciss/c0d0p5     24797380  22273432   1243972  95% /home
/dev/cciss/c0d0p3     29753588  25503792   2713984  91% /data
/dev/cciss/c0d0p1       295561     21531    258770   8% /boot
tmpfs                   257476         0    257476   0% /dev/shm

6. Display Information of File System in MB

To display information of all file system usage in MB (Mega Byte) use the option as ‘-m‘.
[root@tecmint ~]# df -m

Filesystem           1M-blocks      Used Available Use% Mounted on
/dev/cciss/c0d0p2        76525     22644     49931  32% /
/dev/cciss/c0d0p5        24217     21752      1215  95% /home
/dev/cciss/c0d0p3        29057     24907      2651  91% /data
/dev/cciss/c0d0p1          289        22       253   8% /boot
tmpfs                      252         0       252   0% /dev/shm

7. Display Information of File System in GB

To display information of all file system statistics in GB (Gigabyte) use the option as ‘df -h‘.
[root@tecmint ~]# df -h

Filesystem            Size  Used Avail Use% Mounted on
/dev/cciss/c0d0p2      75G   23G   49G  32% /
/dev/cciss/c0d0p5      24G   22G  1.2G  95% /home
/dev/cciss/c0d0p3      29G   25G  2.6G  91% /data
/dev/cciss/c0d0p1     289M   22M  253M   8% /boot
tmpfs                 252M     0  252M   0% /dev/shm

8. Display File System Inodes

Using ‘-i‘ switch will display the information of number of used inodes and their percentage for the file system.
[root@tecmint ~]# df -i

Filesystem            Inodes   IUsed   IFree IUse% Mounted on
/dev/cciss/c0d0p2    20230848  133143 20097705    1% /
/dev/cciss/c0d0p5    6403712  798613 5605099   13% /home
/dev/cciss/c0d0p3    7685440 1388241 6297199   19% /data
/dev/cciss/c0d0p1      76304      40   76264    1% /boot
tmpfs                  64369       1   64368    1% /dev/shm

9. Display File System Type

If you notice all the above commands output, you will see there is no file system type mentioned in the results. To check the file system type of your system use the option ‘T‘. It will display file system type along with other information.
[root@tecmint ~]# df -T

Filesystem  Type   1K-blocks  Used      Available Use% Mounted on
/dev/cciss/c0d0p2 ext3    78361192  23188812  51127616  32%   /
/dev/cciss/c0d0p5 ext3    24797380  22273432  1243972   95%   /home
/dev/cciss/c0d0p3 ext3    29753588  25503792  2713984   91%   /data
/dev/cciss/c0d0p1 ext3    295561     21531    258770    8%    /boot
tmpfs   tmpfs   257476         0    257476    0%   /dev/shm

10. Include Certain File System Type

If you want to display certain file system type use the ‘-t‘ option. For example, the following command will only display ext3 file system.
[root@tecmint ~]# df -t ext3

Filesystem           1K-blocks      Used Available Use% Mounted on
/dev/cciss/c0d0p2     78361192  23190072  51126356  32% /
/dev/cciss/c0d0p5     24797380  22273432   1243972  95% /home
/dev/cciss/c0d0p3     29753588  25503792   2713984  91% /data
/dev/cciss/c0d0p1       295561     21531    258770   8% /boot

11. Exclude Certain File System Type

If you want to display file system type that doesn’t belongs to ext3 type use the option as ‘-x‘. For example, the following command will only display other file systems types other thanext3.
[root@tecmint ~]# df -x ext3

Filesystem           1K-blocks      Used Available Use% Mounted on
tmpfs                   257476         0    257476   0% /dev/shm

12. Display Information of df Command.

Using ‘–help‘ switch will display a list of available option that are used with df command.
[root@tecmint ~]# df --help

Usage: df [OPTION]... [FILE]...
Show information about the file system on which each FILE resides,
or all file systems by default.

Mandatory arguments to long options are mandatory for short options too.
  -a, --all             include dummy file systems
  -B, --block-size=SIZE use SIZE-byte blocks
  -h, --human-readable  print sizes in human readable format (e.g., 1K 234M 2G)
  -H, --si              likewise, but use powers of 1000 not 1024
  -i, --inodes          list inode information instead of block usage
  -k                    like --block-size=1K
  -l, --local           limit listing to local file systems
      --no-sync         do not invoke sync before getting usage info (default)
  -P, --portability     use the POSIX output format
      --sync            invoke sync before getting usage info
  -t, --type=TYPE       limit listing to file systems of type TYPE
  -T, --print-type      print file system type
  -x, --exclude-type=TYPE   limit listing to file systems not of type TYPE
  -v                    (ignored)
      --help     display this help and exit
      --version  output version information and exit

SIZE may be (or may be an integer optionally followed by) one of following:
kB 1000, K 1024, MB 1000*1000, M 1024*1024, and so on for G, T, P, E, Z, Y.

Report bugs to .
Read Also :
  1. 10 fdisk Commands to Manage Linux Disk Partitions
  2. 10 Useful “du” Commands to Find Disk Usage of Files and Directories

Monday, September 2, 2013

15 Practical Grep Command Examples In Linux / UNIX

You should get a grip on the Linux grep command.
In this article let us review 15 practical examples of Linux grep command that will be very useful to both newbies and experts.


First create the following demo_file that will be used in the examples below to demonstrate grep command.
$ cat demo_file
THIS LINE IS THE 1ST UPPER CASE LINE IN THIS FILE.
this line is the 1st lower case line in this file.
This Line Has All Its First Character Of The Word With Upper Case.

Two lines above this line is empty.
And this is the last line.

1. Search for the given string in a single file

The basic usage of grep command is to search for a specific string in the specified file as shown below.
Syntax:
grep "literal_string" filename
$ grep "this" demo_file
this line is the 1st lower case line in this file.
Two lines above this line is empty.

2. Checking for the given string in multiple files.

Syntax:
grep "string" FILE_PATTERN

This is also a basic usage of grep command. For this example, let us copy the demo_file to demo_file1. The grep output will also include the file name in front of the line that matched the specific pattern as shown below. When the Linux shell sees the meta character, it does the expansion and gives all the files as input to grep.
$ cp demo_file demo_file1

$ grep "this" demo_*
demo_file:this line is the 1st lower case line in this file.
demo_file:Two lines above this line is empty.
demo_file:And this is the last line.
demo_file1:this line is the 1st lower case line in this file.
demo_file1:Two lines above this line is empty.
demo_file1:And this is the last line.

3. Case insensitive search using grep -i

Syntax:
grep -i "string" FILE

This is also a basic usage of the grep. This searches for the given string/pattern case insensitively. So it matches all the words such as “the”, “THE” and “The” case insensitively as shown below.
$ grep -i "the" demo_file
THIS LINE IS THE 1ST UPPER CASE LINE IN THIS FILE.
this line is the 1st lower case line in this file.
This Line Has All Its First Character Of The Word With Upper Case.
And this is the last line.

4. Match regular expression in files

Syntax:
grep "REGEX" filename

This is a very powerful feature, if you can use use regular expression effectively. In the following example, it searches for all the pattern that starts with “lines” and ends with “empty” with anything in-between. i.e To search “lines[anything in-between]empty” in the demo_file.
$ grep "lines.*empty" demo_file
Two lines above this line is empty.
From documentation of grep: A regular expression may be followed by one of several repetition operators:
  • ? The preceding item is optional and matched at most once.
  • * The preceding item will be matched zero or more times.
  • + The preceding item will be matched one or more times.
  • {n} The preceding item is matched exactly n times.
  • {n,} The preceding item is matched n or more times.
  • {,m} The preceding item is matched at most m times.
  • {n,m} The preceding item is matched at least n times, but not more than m times.

5. Checking for full words, not for sub-strings using grep -w

If you want to search for a word, and to avoid it to match the substrings use -w option. Just doing out a normal search will show out all the lines.

The following example is the regular grep where it is searching for “is”. When you search for “is”, without any option it will show out “is”, “his”, “this” and everything which has the substring “is”.
$ grep -i "is" demo_file
THIS LINE IS THE 1ST UPPER CASE LINE IN THIS FILE.
this line is the 1st lower case line in this file.
This Line Has All Its First Character Of The Word With Upper Case.
Two lines above this line is empty.
And this is the last line.

The following example is the WORD grep where it is searching only for the word “is”. Please note that this output does not contain the line “This Line Has All Its First Character Of The Word With Upper Case”, even though “is” is there in the “This”, as the following is looking only for the word “is” and not for “this”.
$ grep -iw "is" demo_file
THIS LINE IS THE 1ST UPPER CASE LINE IN THIS FILE.
this line is the 1st lower case line in this file.
Two lines above this line is empty.
And this is the last line.

6. Displaying lines before/after/around the match using grep -A, -B and -C

When doing a grep on a huge file, it may be useful to see some lines after the match. You might feel handy if grep can show you not only the matching lines but also the lines after/before/around the match.

Please create the following demo_text file for this example.
$ cat demo_text
4. Vim Word Navigation

You may want to do several navigation in relation to the words, such as:

 * e - go to the end of the current word.
 * E - go to the end of the current WORD.
 * b - go to the previous (before) word.
 * B - go to the previous (before) WORD.
 * w - go to the next word.
 * W - go to the next WORD.

WORD - WORD consists of a sequence of non-blank characters, separated with white space.
word - word consists of a sequence of letters, digits and underscores.

Example to show the difference between WORD and word

 * 192.168.1.1 - single WORD
 * 192.168.1.1 - seven words.

6.1 Display N lines after match

-A is the option which prints the specified N lines after the match as shown below.
Syntax:
grep -A  "string" FILENAME

The following example prints the matched line, along with the 3 lines after it.
$ grep -A 3 -i "example" demo_text
Example to show the difference between WORD and word

* 192.168.1.1 - single WORD
* 192.168.1.1 - seven words.

6.2 Display N lines before match

-B is the option which prints the specified N lines before the match.
Syntax:
grep -B  "string" FILENAME

When you had option to show the N lines after match, you have the -B option for the opposite.
$ grep -B 2 "single WORD" demo_text
Example to show the difference between WORD and word

* 192.168.1.1 - single WORD

6.3 Display N lines around match

-C is the option which prints the specified N lines before the match. In some occasion you might want the match to be appeared with the lines from both the side. This options shows N lines in both the side(before & after) of match.
$ grep -C 2 "Example" demo_text
word - word consists of a sequence of letters, digits and underscores.

Example to show the difference between WORD and word

* 192.168.1.1 - single WORD

7. Highlighting the search using GREP_OPTIONS

As grep prints out lines from the file by the pattern / string you had given, if you wanted it to highlight which part matches the line, then you need to follow the following way.

When you do the following export you will get the highlighting of the matched searches. In the following example, it will highlight all the this when you set the GREP_OPTIONS environment variable as shown below.
$ export GREP_OPTIONS='--color=auto' GREP_COLOR='100;8'

$ grep this demo_file
this line is the 1st lower case line in this file.
Two lines above this line is empty.
And this is the last line.

8. Searching in all files recursively using grep -r

When you want to search in all the files under the current directory and its sub directory. -r option is the one which you need to use. The following example will look for the string “ramesh” in all the files in the current directory and all it’s subdirectory.
$ grep -r "ramesh" *

9. Invert match using grep -v

You had different options to show the lines matched, to show the lines before match, and to show the lines after match, and to highlight match. So definitely You’d also want the option -v to do invert match.

When you want to display the lines which does not matches the given string/pattern, use the option -v as shown below. This example will display all the lines that did not match the word “go”.
$ grep -v "go" demo_text
4. Vim Word Navigation

You may want to do several navigation in relation to the words, such as:

WORD - WORD consists of a sequence of non-blank characters, separated with white space.
word - word consists of a sequence of letters, digits and underscores.

Example to show the difference between WORD and word

* 192.168.1.1 - single WORD
* 192.168.1.1 - seven words.

10. display the lines which does not matches all the given pattern.

Syntax:
grep -v -e "pattern" -e "pattern"
$ cat test-file.txt
a
b
c
d

$ grep -v -e "a" -e "b" -e "c" test-file.txt
d

11. Counting the number of matches using grep -c

When you want to count that how many lines matches the given pattern/string, then use the option -c.
Syntax:
grep -c "pattern" filename
$ grep -c "go" demo_text
6

When you want do find out how many lines matches the pattern
$ grep -c this demo_file
3

When you want do find out how many lines that does not match the pattern
$ grep -v -c this demo_file
4

12. Display only the file names which matches the given pattern using grep -l

If you want the grep to show out only the file names which matched the given pattern, use the -l (lower-case L) option.

When you give multiple files to the grep as input, it displays the names of file which contains the text that matches the pattern, will be very handy when you try to find some notes in your whole directory structure.
$ grep -l this demo_*
demo_file
demo_file1

13. Show only the matched string

By default grep will show the line which matches the given pattern/string, but if you want the grep to show out only the matched string of the pattern then use the -o option.

It might not be that much useful when you give the string straight forward. But it becomes very useful when you give a regex pattern and trying to see what it matches as
$ grep -o "is.*line" demo_file
is line is the 1st lower case line
is line
is is the last line

14. Show the position of match in the line

When you want grep to show the position where it matches the pattern in the file, use the following options as
Syntax:
grep -o -b "pattern" file
$ cat temp-file.txt
12345
12345

$ grep -o -b "3" temp-file.txt
2:3
8:3

Note: The output of the grep command above is not the position in the line, it is byte offset of the whole file.

15. Show line number while displaying the output using grep -n

To show the line number of file with the line matched. It does 1-based line numbering for each file. Use -n option to utilize this feature.
$ grep -n "go" demo_text
5: * e - go to the end of the current word.
6: * E - go to the end of the current WORD.
7: * b - go to the previous (before) word.
8: * B - go to the previous (before) WORD.
9: * w - go to the next word.
10: * W - go to the next WORD.

Additional Grep Tutorials

Awesome Linux Articles

Following are few awesome 15 examples articles that you might find helpful.

Saturday, August 17, 2013

How to Fix Dell Laptop Hard Disk 0146 Error Code

Something has gone bad and you are not ready to accept that your computer, which was working fine just a moment before, now shows an error code 0146, indicating that its hard drive has sunk. Well, yes the error code 0146 is related to Dell laptop’s hard drive, which begins to experience problems when it becomes full or due to a program’s corruption, virus infections, or other miscellaneous reasons. Thinking of a bad hard drive may let you think of losing data stored onto it and may make you feel bad and sad. Replacing the hard drive is a recommended solution but while it is, we shall suggest some other workarounds also which can help you fix the error code 0146 on your Dell laptop.
**As you go through the steps, you may need help of your Dell support manual to navigate through options mentioned here. So, keep your Dell laptop support manual handy for help. You must perform each step one after another to check if the problem has fixed.
Step 1: Run a Virus Scan
A bad malware can corrupt your hard drive and result in this error. Open your antivirus, update it with the latest security definitions and run a full virus scan. Delete the resulting infections and run another online virus scanner to double sure that it is free of infections. When done, exit antivirus and start up a new program or play your favorite song. The error should be gone away and your computer should work fine.
Step 2: Run computer in Safe Mode and clean boot
Disconnect all the attached devices viz. USB keys, router, wireless printer etc. and turn off your computer. Turn it on again and press & hold the “F8” key quickly before the Windows logo comes up. Select “Safe mode with networking” and hit Enter. Open System Configuration Utility from theStartRun> type “msconfig” and click OK. In the System Configuration Utility window, clickGeneralSelective Startup> uncheck the “Load Startup Items” box> Services> check the “Hide All Microsoft Services” box> Disable AllApplyOK. Restart your laptop when prompted. If the issue has resolved, go back to System Configuration Utility window> General> click Normal StartupOK> restart computer. If the problem persists, run “chkdsk” utility to check and fix hard drive errors. Open Command Prompt and type “chkdsk /f /r C:” Hit Enter to proceed. When prompted, press “Y” to fix the errors. Repeat this procedure for other drives also if applicable. When done, restart your computer.
Step 3: Run hard drive diagnostic
Before you do this step, make sure that your Dell laptop is fully charged as the diagnosis may take a good amount of time. If your laptop is not charged or half charged, plug its AC adapter into a power outlet to avoid losing charge and halting the diagnosis. Now turn off your Dell laptop. Now power it on again and repeatedly stroke the “F12” key on the keyboard unless you see the option “Diagnostics”. In newer Windows versions, you may need not repeatedly press “F12” as it comes on quickly when the laptop is powered on. Click “Diagnostics” and a series of testes will start running one after another to detect the problem. When the test is completed, and still results in 0146 error code, click “Yes” to continue. When you see a colorful screen, click “Yes” continue troubleshooting. If the error continues, move on to the next step.
Step 4: Change to SATA Drive
Go to Dell laptop BIOS and check whether the hard drive configuration has been changed to AHCI SATA from SATA Drive. If it is changed, change it back to “SATA Drive”. When done, back up all your data, delete all partitions (in other words format your hard drive) and reinstall Windows from scratch. That’s it! You will never get back this error.
Step 5: Check hard drive with another computer
Connect your hard drive to another computer (if you have one or your friend’s) using the SATA cable and check whether it is detected on it or not. If the hard drive is detected, recover all your data and back it up there. Run a hard drive diagnostic mentioned in the above step and fix errors. If the hard drive is not detected on this computer also, take expert help to recover your data and contact Dell technical support for a hard drive replacement.
Step 6: Is your Dell laptop under warranty?
If your Dell laptop is brand new and is in warranty period, contact Dell for a free hard drive replacement. If it’s out of warranty period, you may need to shell out for the hard drive.

Monday, July 15, 2013

HOW TO MAKE BOOTABLE USB PEN DRIVE FOR WINDOWS 7 OR 8

Bootable Usb Pen Drive

Bootable Usb Pen drive is simple and fast way to format your PC or Laptop. After formatting you can easily install windows in your system. Bootable usb pendrive has several advantage as like easy formatting, easy copy and past windows file and after that easy to installing windows. Now we are discussing some important step to make bootable pen drive.

Advantages :

  • Installing process through bootable usb pen drive is much better then DVD.
  • Easy to carrying.
  • Easy to handle and no need to expert. 
  • Best option for all who haven’t DVD drive in his PC or Laptop.

Requirement :

  • Blank (empty) Pen drive with minimum capacity of 4Gb.

Process :


Step 1 :

Plug-in your pen drive in Laptop.

Step 2 :

Go to Start  >> Type Cmd  (in search program and file [Press Enter]
After pressing Enter command prompt will open.
On your Caps lock

Step 3 :

Type  DISKPART   [Press Enter]
bootable usb pen drive

Step 4 :

Type  LIST  DISK    [Press Enter]
It will show all available disk in your system. Disk 0 is usually hard disk of your system. In my case Disk 1 is Usb pen drive (This can be different in your case so plz make sure )

Step 5 :

Type  SELECT  DISK  1  [Press Enter]

Step 6 :

Type  CLEAN  [Press Enter]

Step 7 :

Type  CREATE  PARTITION  PRIMARY   [Press Enter]

Step 8 :

Type  SELECT  PARTITION  1  [Press Enter]

Step 9 :

Type  ACTIVE  [Press Enter]

Step 10 :

Type FORMAT  FS=NTFS  [Press Enter]
Wait Until 100% complete.

Step 11 :

Type  ASSIGN  [Press Enter]

Step 12 :

Type EXIT [Press Enter]
Bootable Usb Pen driveNow bootable usb pen drive is ready to use. After making this copy and paste windows 7 or 8 in your pen drive. It is easiest way to install windows 7 or 8 in your  system.
When you want to install windows, plug-in bootable pen drive and restart the system and press boot function key as per different system (f1——-f12) .

Note :

Before making bootable usb pen drive plz make sure that you are using only one Pen drive at this time. This process is only for windows 7 or 8 not for Xp.
Download (windows to flash )