• Displaying Manual or Help Page

# man find

• Getting Short Description

# man -f ifconfig

• Getting List of commands using keyword

# man -k “network”

• Converting Manual Page into Portable Format [ Text , PDF , PS ]

• • For Text File conversion
    # man ls | col -b > lstext.txt
  • For PDF or PS conversion# man -t ls > lsps.ps

    # man -t ls | ps2pdf – > lstext.pdf

2. apropos - search the command short description with the given keyword

• General Syntax

#apropos “print”

• Pattern Matching

#apropos -r “^[p]+[g]$”

[This pattern will match the command description word

starting with "p" and ends with "g" ]

3. cd – changing the current directoy to some destination directory

# pwd [ Current Working Directory]

# cd /opt/ [chnage to /opt]

# cd .. [ change to root]

4. ls - List Directories and Files

# ls [ display all files and folders ]

# ls -l [ display files with all information ]

# ls -a [ display hidden files also ]

# ls -R [ display the folder contents ]

# ls -i [ display the index number of each file ]

5.cp – copying folders and files from source to destination.

5.1 Copying Files

# cp kavidhai.pdf /opt/

[copy the file kavithai.pdf into /opt folder]

# cp kavidhai.pdf sam.txt /opt/

[copy the files kavithai.pdf and sam.txt into /opt folder ]

5.2 Copying Folders

# cp -r uploads/ /opt/

[Copy the folder uploads and its content into /opt folder]

6. rm – delete files and folders

# cd /opt/uploads

# rm kavidhai.pdf

[Delete kavithai.pdf from uploads folder ]

# cd ..

# rm -r uploads/

[Delete the folder uploads/ and its content from /opt]

7. cat - create ,display and concatenate the file (s)

7.1 Create new file

# cat > sample.txt

Hello

[This syntax will create new textfile you can use ctrl+c

for saving and exit from the editor. ]

7.2 Dispaly the file contents [Read Only]

#cat sample.txt

Hello

7.3 Concatenating Files

# cat > sample1.txt

Welcome to OpenPeata

^C

# cat sam.txt sample1.txt

Hello

Welcome to OpenPeata

8. history – User commands in terminal will be stored into hitory configuration file.

# history | tail -2

48 cat > sam.txt

49 cat sam.txt

[This command displays last 10 histories, to display entire history type only history command (#history)]

#history -c [Clears all history ]

9. find – search for files in a directory

# find /opt -name “eclipse”

[This command will search the files and folders contains the name 'eclipse' in /opt directory]

10. tar - Cretae Append , Delete , Extract the archive files

#tar -cf my.tar a.txt b.txt [Create my.tar from files ] a.txt and b.txt.

#tar -tvf my.tar [List all files in my.tar]

#tar -xf my.tar [ Extract all files from my.tar]

#tar -xzvf eclipse.tar.gz [ Extract tar.gz file]

#tar -xjvf octave.tar.bz2 [Extract tar.bz2 file]

Download the Reference Card

This command is used for copying folders and files from source to destination.

Copying Files

# cd /home/anthoniraj/uploads/
# cp kavidhai.pdf /opt/ [copy the file kavithai.pdf into /opt folder]
# cp kavidhai.pdf sam.txt /opt/ [copy the files kavithai.pdf and sam.txt into /opt folder ]

Copying Folders

# cp -r uploads/ /opt/ [Copy the folder uploads and its content into /opt folder]

2. rm command – delete files and folders

# cd /opt/uploads
# rm kavidhai.pdf [Delete kavithai.pdf from uploads folder ]
# cd ..
# rm -r uploads/ [Delete the folder uploads/ and its content from /opt]

#apropos “print”

apropos Sample Output Page

#apropos -r “^[p]+[g]$”

pg (1)               – browse pagewise through text files

This pattern will match the command description word starting with “p” and ends with “g”. Like this user can create your own pattern for finding commands.

cd  – Change Directory
cd command is used for changing the current directoy to some destination directory which you want to use. First you need to find which directory currently you are using, for that you can use “pwd – present working directory” command.
Examples

anthoniraj@Ubuntu:~$ pwd

/home/anthoniraj

I am using home directory , here anthoniraj is the user of the system. Now i want to change home directory to “/opt”

anthoniraj@Ubuntu:~$ cd /opt/

anthoniraj@Ubuntu:/opt$

You can also use dot (.) for changing directory

anthoniraj@Ubuntu:/opt$ cd ..

anthoniraj@Ubuntu:/$ pwd

/

[/ - root directory]

“Linux: the operating system with a CLUE… Command Line User Environment”.

Now a days , everything you can do with GUI mode, even though graphical mode is user friendly , only user can do their work more faster way using commands. As a Linux beginners , you need to know at least some basic commands which would be useful for your frequent activities in Linux. Here i have given 10 basic commands for beginners to work with some basic regular tasks in Linux .

1. man
2. apropos
3. cd
4. ls
5. cp
6. rm
7. cat
8. history
9. find
10. tar

Every command has lot of options , but i am going to give only the basic options for user regular activities. Please refer coming articles for understanding these 10 commands.

2.Reboot
o init 6
o shutdown -r now
o reboot

3.Enter single user mode:
o init 1

Syntax :
tail [options] filename

[Source from Wikipedia]
By default, tail will print the last 10 lines of its input to the standard output. With command line options the number of lines printed and the printing units (lines, blocks or bytes) may be changed. The following example shows the last 20 lines of filename:
tail -n 20 filename

This example shows the last 15 bytes of all files starting with filename :
tail -c 15 filename

This example shows all lines of filename from the second line onwards:
tail -n +2 filename

Using an older syntax (still used in Sun Solaris as the -n option is not supported), the last 20 lines and the last 50 bytes of filename can be shown with the following command:
tail -20 filename
tail -50c filename

However this syntax is now obsolete and does not conform with the POSIX 1003.1-2001 standard. Even if still supported in current versions, when used with other options (like -f, see below), these switches could not work at all.

File monitoring

tail has a special command line option -f (follow) that allows a file to be monitored. Instead of displaying the last few lines and exiting, tail displays the lines and then monitors the file. As new lines are added to the file by another process, tail updates the display. This is particularly useful for monitoring log files. The following command will display the last 10 lines of messages and append new lines to the display as new lines are added to messages:

tail -f /var/adm/messages

To interrupt tail while it is monitoring, break-in with CTRL-C. This command can be run “in the background” with &, see job control.

2.cd – change directory path
# cd [dirname]–> switches into specified directory
# cd .. –>moves one directory up
# cd ../../ —> moves two directories up (and so on)
# cd –> brings you to highest level of your home directory

3.rm – delete files and directories
# rmdir –> removes empty directory
# rm –> removes file name
# rm -r –> removes directory including its content, but asks for confirmation, ‘f’ argument turns confirmation off

4.mv – move or rename the file or directory
# mv [name1] [name2] –> renames directories or files
# mv [name] [dir]–> moves file/directory as specified in path
# rename [oldfilename] [newfilename] [oldfilename]

5.cp -copy files and directory
# cp [file] [path] –> copy file/directory as specified in path (-r to include content in directories)

6. pwd –> present working directory
7. ls –> content of pwd
8. ll –> similar as ls, but provides additional info on files and directories
9. ll -a –> includes hidden files (.name) as well
10. ll -R –> lists subdirectories recursively
11 ll -t –> lists files in chronological order
12.dir – display the directory contents
13.stat [filename]–> provides all attributes of a file

Syntax :
head options filename

Examples
1) Sample file

root@VIT#vi sample.c
//Write a program to display the name and address of the computer that we are currently
//working on.

#include
#include
#include
#include
#include
int main(int argc,char *argv[])
{
struct hostent *he; // note the spelling it is hostent
printf(“%d “,argc);
printf(“%s “,argv[0]);
printf(“%s \n”,argv[1]);
if (argc!=2)
{
printf(“Error in input”);
exit(-1);
}
he=gethostbyname(argv[1]);
if (he == NULL)
{
printf(“Get host by name error”);
}
printf(“Name == >> %s \n”,he->h_name);
printf(“Address == >> %s \n”,inet_ntoa(*((struct in_addr *)he->h_addr)));
return 0;
}

2) Noraml head command display the first 10 lines from the file
root@VITX#head sample.c
//write a program to display the name and address of the computer that we are currently
//working on.

#include
#include
#include
#include
#include
int main(int argc,char *argv[])
{

3) Option -c print the first N bytes of each file

root@VIT#head -c 100 sample.c
//Write a program to display the name and address of the computer that we are currently
root@VITLINUX#head -c 500 sample.c500 sample.c
//Write a program to display the name and address of the computer that we are currently
//working on.

#include
#include
#include
#include
#include
int main(int argc,char *argv[])
{
struct hostent *he; // note the spelling it is hostent
printf(“%d “,argc);
printf(“%s “,argv[0]);
printf(“%s \n”,argv[1]);
if (argc!=2)
{
printf(“Error in input”);
exit(-1);
}
he=gethostbyname(argv[1]);
if (he == NULL)
{
printf(“Get

4) Option -n print the first N lines instead of the first 10

root@VIT#head -n 5 sample.c
//Write a program to display the name and address of the computer that we are currently
//working on.

#include
#include
root@VITLINUX#head -n 6 sample.c
//Write a program to display the name and address of the computer that we are currently
//working on.

#include
#include
#include

Syntax

mv [OPTION]… SOURCE… DIRECTORY

Example
1. [root@myclient1 ~]# mv sample.c /home/ameer/

rename command is used for rename the given file and also we can use mv command for rename the file

Syntax
rename from to file…
mv SOURCE DEST

Examples
1. [root@myclient1 ~]# rename abc.pl new.c abc.pl
[root@myclient1 ~]# ls
3318.PDF a.sh file1 new.c

2. [root@myclient1 ~]# mv new.c new1.c
[root@myclient1 ~]# ls
3318.PDF a.sh file1 new1.c

Syntax
cp options source destination

Examples :
1. For copying one file from one location to other

[root@MB327SCS068 antony]# cp sample.c /home/admin/

Now the sample.c (Which is in /home/antony) has been copied into /home/admin

2. For copying more than one file from one location to other

[root@MB327SCS068 antony]# cp sample.c sample2.c /home/admin/

Now the sample.c and sample2. (Which is in /home/antony) have been copied into /home/admin

3. To copy whole directory to other location

[root@MB327SCS068 antony]# cp -R /home/antony/ /mnt/

Now the /home/antony / directory and (-R => recursively) sub directory have been copied into /mnt