Hi,

I am following a tutorial in which I have to use the cat command to create the module.conf file. However, each time I type: $ cat >> /etc/asterisk/modules.conf, the cursor just starts a new line and nothing else happens. Please help, I am new to linux.

Ernie

if you want to create new empty file use below command.

touch /etc/asterisk/modules.conf

or if you only want to use cat >> /etc/asterisk/modules.conf . after hitting the command press CTRL+ z .
file will be created

What tutorial is this? cat is used to dump the contents of a file to the terminal, it's not used to create a new file (you should use touch, as sharadchhetri mentioned).

Actually I disagree. Cat may be used to create the contents of a file using the method mentioned. In fact it is quite common in the (C)LFS world as an editor may not yet be installed, example here (section 10.7.3)

If you look at the link I provided, the alternative to requiring ctrl-d is:
In this instance the final EOF (this can be any string) must be at the start of the last line and the only thing on the line.

2 members found this post helpful.

Thanks, Grail! That was a new one on me.

Me too, though I don't really understand the point of using cat for this vs using echo or some other more "common" approach. I guess it's just another one of those cases where there are 100 different ways to do some task, and which one is best just depends on who you ask.

Always different horses for courses, however, on the subject of cat v echo in this scenario:
You can also quote the EOF variable to prevent parameter expansion if required (see here documents)

cat simply takes all the input given to it from sdtin or a list of files, and prints it to stdout. This has the effect of "concatenating" all input into one continuous stream.

It's traditional uses are to combine multiple files into one (hence the name), as a quick way to print out the contents of a file for reading, and to redirect user input into files or commands, as grail demonstrated. One thing you should generally not use it for, however, is to feed the contents of a single file into another command (the Useless Use Of Cat). Just use the shell's "<" redirection for that, if the command in question can't read files directly.

There are also a handful of useful input filtering options built into it. cat -A will display all non-printing characters, for example, and cat -n will prefix the output with line numbers.

In the OP code, cat wasn't given any files to read, or any scripted form of stdin input (such as the heredocs demonstrated above), so it just sat there listening to stdin for something to print. If you had typed something into the shell then cat would have printed it to stdout (redirected to the file in this case), and continued doing so until it received an EOF (end-of-file) signal or was otherwise externally terminated.

1 members found this post helpful.

I got it. Thank you all for the help.

Please mark as SOLVED once you have a solution.

grail gave rt. way to use cat command.
with ctrl+z it will go backend but stopped also.