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Creating File using the CAT Command

 
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# 1  
Old 01-12-2010
Creating File using the CAT Command
Hello ,

I am newbie to UNIX platform .
I have read that there are two ways of creating files that is using
1.) Cat 2.) touch .

With Cat Command i am unable to create a File , i is saying No file or Directory exists

I logged in with root as user .

please help
# 2  
Old 01-12-2010
Tools creating file with cat command
Code:
cat > sample

now, type data in
you can press Enter/Return
when done, press
Code:
Control and d keys

# 3  
Old 01-12-2010
cat is not a command for creating files. cat is a method for concatenating files. (see man cat.) It creates files the same way as any command capable of producing any output whatsoever -- shell redirection allows you to put its output into a file.

Code:
# Echo prints to stdout
$ echo asdf
asdf
# Echo prints to new empty file 'newfile'
$ echo asdf > newfile
# printf prints to stdout
$ printf "%02d\n" 9
09
# printf prints to new empty file 'newfile'
$ printf "%02d\n" 9 > newfile
# printf appends to file 'newfile'
$ printf "%02d\n" 9 >> newfile
# etc...

touch on the other hand is a command for creating new files(and updating their timestamps).
This User Gave Thanks to Corona688 For This Post:
linuxford
# 4  
Old 01-12-2010
At first it is very important in *nix environments to have an eye on case sensitvity. It is a difference to use cat Cat or CAT. Only the 1st will work, but that just by the way.

cat is for showing the content of an already existing file. It alone will not create a file - you will have to redirect output with a > sign into a new file. Maybe this is more appropriate:
Code:
# writes text into the file "newfile"; overwrites it's content if it already exists
echo "Content of my new file" > newfile
# writes text into the file "newfile"; appends content if it already exists
echo "Content of my new file" >> newfile
# creates empty file named "newfile"
> newfile
# creates empty file named "newfile"
touch newfile

# 5  
Old 01-12-2010
Thank you very much .

Great Forum with instant replies .

Thanks to the site creator .Smilie
# 6  
Old 01-12-2010
The equivalent of "touch new_file_name" is:

Code:
cat /dev/null > new_file_name

# 7  
Old 01-12-2010
Quote:
Originally Posted by methyl
The equivalent of "touch new_file_name" is:

Code:
cat /dev/null > new_file_name

But only for a new file.

Where just
Code:
> new_file_name

would do.

Corona688 is right. Using redirection with any tool will create a file, so the question is ultimately futile.
Last edited by Scott; 01-12-2010 at 12:31 PM.. Reason: rewording
 
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