Tuesday, October 23, 2012

cat and more

“cat” command

 

the cat command can be used to display contents of files ,write into files or to concatenate files.

Displaying a file using “cat” command
     
        $ cat filename

   ex:
  


Writing into files using “cat” command

        $ cat > filename
            #things to be
            # written
            #in the file
            #

once you finish press enter to go to a new line and then press ctrl +D to close file.

   ex:
 



Appending in to a file using “cat” command

      similar to writing a file using cat but use >>

           $ cat >> filename
             # new content
            #to be appended
            #to the file

   ex:



Concatenating files using “cat” command

several files can be concatenated to a single file using cat command

           $ cat file1 file2 file3 > newFile

(* this is useful to merge a file that has been split into several parts by the “split” command )

   ex:



“more” command


The “cat” command displays the entire file at once. So it maybe a disadvantage when viewing a large file using cat because we may only see the last part of the file. Therefore viewing large files the “more” command is a better option.

The “more” command displays a file page by page. 

           $ more filename


1 comment: