Bashscripts.org

Hey,

I need the following script.
for example

./showme test.txt 15
the first variable is the filename
the second one is a number to show 15 lines from the tail of the fail.

If the first variable doesn`t exist it should show error
if the second variable doesn`t exist it should take 10 lines of the tail.
and show them on screen.

Can someone help me.

Thanx

Wait a minute... Is this a trick question or a homework project? You just described the "tail" command!

-Jeo

It`s not a trick question.
And it`s not homework,
But I have an exam coming soon and there will be some scripting with tail commands.
and I never used tail before.
So I tought if I have an example then I can integrate it in other questions.

Right on

Here's how I'd do it. I put some comments in, but let us know if you need help with anything!



Hope this helps!
-J

Ah thanx
And thank you for explaining everything.
It`s now crystal clear.

But I don`t understand a few things that you wrote.
I had to alter them because it didn`t work at first.
Maybe you can explain.

First in the first line you wrote /sh is that something else then /bash

second in the first if section you wrote exit 1 (What does the 1 do??)

and last in the last line you used {}, I had to remove does.
tail -n $lines $file And I used this.

and mayby a very stupid question.
For remarques I learned to use 1#, you used ## is there a differents.

Thank you again
I`ve learned a lot.


by the way
The code below is how it works on my computer.

Hi! I'm glad it worked! Looks like I need to work on making my scripts more universal...

>> First in the first line you wrote /sh is that something else then /bash
/bin/sh on most systems is actually a link to /bin/bash on many systems. sh is the basic shell, the predecessor to bash.

>> second in the first if section you wrote exit 1 (What does the 1 do??)
The "1" is the exit status. It's not really necessary in this case unless you plan on taking some other action based on the exit status. 1 means 'error'

>> and last in the last line you used {}, I had to remove does.
>> tail -n $lines $file And I used this.
That's odd. I thought that the {brackets} were a universal thing. Typically they're used if your variable is included in the middle of some other text, to provide some separation. They're not necessary in this case though, so removing them works great.

>> and mayby a very stupid question.
No such thing!

>> For remarques I learned to use 1#, you used ## is there a differents.
No difference, just a bad habit on my part You only need 1#