UNIX for Dummies Questions & Answers

Hi--

I'm trying to figure out how to use cat more wisely. I have the following command, which works, but I'd like to understand how to get it to work more clearly and efficiently.

cat 'my file.001' 'my file.002' 'my file.003' 'my file.004' 'my file.005' 'my file.006' 'my file.007' 'my file.008' 'my file.009' 'my file.010' > 'my file'

But I think you're supposed to be able to do

cat file.* > file

Unfortunately, the quotes are preventing the wildcard from working. So my first question is, is there a way to get the wildcard thing to work when you need to use quotes?

The second thing is after running the command, nothing happens. I get no feedback as to what's happening. So the second question is, is there a way to make cat more verbose?

Thanks.

You can use double-quotes to tell the shell not to split arguments on whitespaces, but still substitute globs and variables, eg:

Code:

cat "my file.*" > 'my file'

As for verbosity, cat isn't really that telling. You could put another command at the end to tell you that it's done, or you'll have to use some coding:

Code:

[ -f 'my file' ] && rm 'my file'
for file in "my file.*"
do
    echo "Appending ${file}"
    cat "$file" >> 'my file'
done

Actually, I found yet another way to do this. Just place the wildcard outside the quotes:

Code:

cat 'my file.'* > 'my file'

But I still like the double-quotes better

As far as the verbose command goes, sorry for my n00bness, but do I just use that whole thing in terminal, or do I need to make a script of some kind?

If it's a one-shot thing, just copy & paste it into a terminal. If you need it more than once, put it into a file, write a shebang

Code:

#!/usr/bin/ksh

into the very first line, save. Note that it will always look for 'my file.*' files in the current directory.

Cool

Thanks very much.

---------- Post updated at 03:09 PM ---------- Previous update was at 01:20 PM ----------

Well, I checked out the mini script, and it isn't actually working.

Here's what I found. First, it doesn't look like double-quotes matter. You still get file not found errors. Only by placing the * outside the quotes, or double-quotes in this case, are the files recognized.

As well, it seems that instead of appending one file to the next, somehow, at least the way I tried it, the output file was being rm before the next append, so each file was simply appending to a now non-existing file.

As I understand it, wherever you say "my file" that means the filename of the output file, correct? So then the only place we're referring to the input files are the line:

Code:

for file in 'my file.'*

Is that right?

You're right, the asterisk should be outside the quotes. Sorry, should have caught that, correct version below. But I can' reproduce your other error (disappearing output file).

Yes, when I say 'my file' I mean the output file, and 'my file.*' refers to the input files, as per your original post. and the for-loop is the only line that references the input files by name. Inside the loop, the name of the current file in the variable 'file'.

Correct code

Code:

#!/usr/bin/ksh

[ -f 'my file' ] && rm 'my file'
for file in 'my file.'*
do
    echo "Appending ${file}"
    cat "$file" >> 'my file'
done

np

I think I had forgotten the # command at the top. That works perfectly, of course.

Thanks again.