input from a file ??

FredrikN · 03-29-2002, 03:15 AM

Hi.
Maybe someone can help me with this problem.
Let say I want to run the command cat test.txt grep -v
and then I want to get the rest of the command from some textfile.

I tried
cat test.txt grep -v < textfile.txt

and there are many lines in the textfile
that looks like this
192.168.0.1
192.168.0.2
192.168.0.3

I know I can do this with perl or C but it will be much quicker and easier if the < stuff will work.

Maybe someone can help me with this problem ?

Thanks.

Manish · 03-29-2002, 04:28 AM

cat test.txt | grep -v `cat textfile.txt`

Note that ` character is the one besides the top numeric 1 key (below Escape key).

I have not tested it, but hope it works.

FredrikN · 03-29-2002, 05:36 AM

Thanks, works great

)

I have one more question about this.

If the textfile looks like this, it's a file with user and their passwords and home dirs.
E.x.

cool -p hithere -b /home/xxx/
fast -p fast -b /home/xxxx/

So if I run
useradd `cat usersfile.txt`
there can only be one user in the textfile.

Is it possible to run the useradd command for each line in the textfile.

I wrote a perl script for this a year ago, but if it could be solved with this stuff I'm talking about it would be great :-)

Thanks

Manish · 03-29-2002, 07:49 AM

I guess the best tool to use in this case is awk. See the man page for awk to see what parameters to use to execute a command with every line of a text file.

FredrikN · 03-30-2002, 12:25 AM

Thanks.
awk was the right tool.

Works fine now :-)

//FredrikN

Manish · 03-30-2002, 12:53 AM

cool.