| Command | Description |
|---|---|
| touch | Creates the empty file(s) if it does not exist, Otherwise change the timestamp of file |
| cat | 1.creates the file and save the content 2.Display the file contents 3.Append the content in existing file |
| file | Displays wether its file or directory |
| more | Pagewise display with % |
| less | Pagewise display without % |
| mkdir | Creates the new directory |
| cd | To change the directory |
| rm | To remove or delete the files / directories |
| rmdir | To remove a empty directory |
| ls | To list all files and directories of target directory |
| cp | Copy file(s) from source to destination |
| mv | Move the file(s) from source to destination |
| ln | To make hard or soft link netween the files |
touch command
Used to create the empty file ,it is also used to change the timestamp of existing files
Syntax
$ touch [option] file_name(s)
Examples
To create multiple empty file at a time ,type below command
$ touch file1 file2 file3 file4
To change both the access and modification times to the current time of existing file file1
$ touch -am file1
To use the times of file1 for file2, use oprion -r(reference) as below
$ touch -r file1 file2
The -d and -t options allow the user to add a specific last access time, to change the last access time of file1 to 10 Mar 2014 09:30 would be enclosed in single quotes
and used as follows
$ touch -d '1 Mar 2014 09:30' file1
cat command
Cat can be used for the following purpose
1.To reading or display the content of file
2.New file creation
Syntax
$ cat [option] [filename]
Examples
To reading or display content of file1 ,write below command
$ cat file1
To display the content of more than one files
$ cat file.txt abc.txt f1.txt
The above command will display the content of files in same order ,first it will show the content of file.txt then below that abc.txt then in last f1.txt
To create a new file and writing some content in file.
$ cat > file1.txt
----
----
ctr+d (to save all content in file1.txt)
----
----
ctr+d (to save all content in file1.txt)
Note : if file1.txt already exist then new data will get override.
To append the data in existing file
$ cat >> file1.txt
----
----
write some data and hit 'ctr+d' to save the file1.txt
----
----
write some data and hit 'ctr+d' to save the file1.txt
file command
To check type of file ie: whether it is file or directory.
Syntax
$ file [option] [file/dirname]
more command
To display page wise ,useful when file having more pages which can not be display at a time on the computer screen.
The more command allow you to reading the content from page1
$ more file1.txt
less command
Similar to more command.
This command allows you to view a text file without fear of accidently modifying it, as you would with a text editor
$ less file1.txt
mkdir command
Creates the directory in the current directory, if they do not already exist.
Syntax
$ mkdir [option] [dirname]
Examples
To create a directory dir1 in current directory
$ mkdir dir1
To create a dir in a path ,suppose i would like to create a directory dir2 inside another directory name 'freelancer'
Then we need to give the path of the directory 'freelancer' followed by new directory 'dir2' as follow
$ mkdir /home/mukesh.kumar/Desktop/freelancer/dir2
(or)
--in general
$ mkdir path/dir2
(or)
--in general
$ mkdir path/dir2
To create the hierarchy of directories ,use -p(parents) option
$ mkdir –p dir1/dir2/dir3
cd command
To change the shell working directory
Following command will change current directory to dirname if dirname is present in current directory
$ cd dirname
To change the directory in the mentioned path
$ cd path/dir1
To changes to the home directory
$ cd (or) $ cd ~
To changes to the root directory (i.e. />)
$ cd /
To changes to the Parent directory
$ cd ..
rm command
Used to delete the file or directory.
Syntax
rm [option] [-r directories] [filename]
Examples
To remove multiple files
$ rm file1 file2 file3 [file4..]
To remove a directory recursively
$ rm -r dirname
To remove file interactively
$ rm -i filename.txt
rm: remove regular file `filename.txt'?
rm: remove regular file `filename.txt'?
Note : if rm command used by using '-i' option it will always ask user to confirm by displaying a message.
Removing forcefully
Assume filename is not having write permission for the user. If the user is giving the below command
$ rm filename
It will display confirmation message before removing the file.
But if user is giving the command with ‘-f’ option as follows:
$ rm –f file_name
It will remove the file forcefully without displaying confirmation message
To remove a file whose name starts with a `-', for example `-foo',
use one of these commands:
$ rm -- -foo
(or)
$ rm ./-foo
(or)
$ rm ./-foo
rmdir command
rmdir can be use to remove the empty directory
$ rmdir emptydir
ls (list) command
List information about the FILEs (the current directory by default).
Syntax
$ ls [option] [file]
Note : To check the various option ,use the following command
$ ls --help
Examples
To list all file and directories of current directory
$ ls
To list files and directories of target directory in long format
(includes accesspermissions, size of file, last modification date & time, no of links etc.)
$ ls -l
To list files and directories of target directory
$ ls dirname
To list all the files and directories (including hidden) of target directory
$ ls -a dirname
To list files and directories of target directory in reverse order.
$ ls -r dirname
Note : by default it shows in alphabetically.
To list files and directories of target directory with their inode value.
$ ls -i dirname
To list all the files and directories of target directory recursively
$ ls -R dirname
To list files and directories of target directory with information of format of file
(ie : directory name with ‘/’ as suffix, executable files with ‘*’ as suffix etc.)
$ ls -F dirname
To list with inode value
$ ls -i dirname
To list all the files and directories(including hidden files) of target directory in long format
$ ls -al dirname
To list files and directories with inode values recursively of target directory in long format
$ ls -iRl dirname
To list files and directories with last modified in reverse order
$ ls -ltr dirname
cp command
To copy files and directories from source to destination.
Synatx
$ cp [option] source destination
Examples
To create copy of file1.txt with name file2.txt in same directory
$ cp file1.txt file2.txt
To create copy of multiple source file(s) with same name in source directory
$ cp file1.txt [file2.txt] dirname
To copy dir1 or content of dir1 in dir2
$ cp -r dir1 dir2
Note : if dir2 is not present : create dir2 in current dir,copy content of dir1 in dir2
if dir2 present : COPY sub tree structure rooted at dir1 in dir2
( inside dir2 we will get dir1)
To copy files interactively. It will ask for confirmation by displaying a message to the user but only in the case of overwriting.
$ cp –i source destination
mv command
Used to rename source file/directory to destination name
Move source file/directory to destination directory
Syntax
$ mv [option] source destination
To rename source file with destination name
$ mv file1.txt file2.txt
To move source files in destination directory
$ mv file1.txt [file2.txt] dirname
To move dir1 or content of dir1 into dir2
$ mv -r dir1 dir2
Note : if dir2 is not present :rename dir1 with name dir2
if dir2 present then move sub tree structure rooted at dir1 in dir2
To Move or rename interactively. It will ask for confirmation by displaying a message to the user but only in the case of overwriting.
$ mv –i source destination
ln( link ) command
To create hard and soft link between the files
There are two types of link we can create
1.Hard Link :
While creating a link from source to Destination file.The changes done in the source file will be effected in destination file.
But when The source file is deleted the destination file remains the same.
2.Soft Link :
While creating a link using soft link from source to destination file → the changes done
in the source file will be effected in Destination file too.
But when the source file is deleted the destination file also gets invisible. i.e when u tried to check the destination file its says no such file or directory
To make hard link between the file
$ ln sourcefile destinationfile
To makes soft(or symbolic) link between files
$ ln -s source destination
Note : we can not create hard link for directory
