Need help with a really basic assignment, probably gonna take you 5 mins to do.but it worse 7% to me
1. The problem statement, all variables and given/known data:
I am a international student who is studying in Australia, my mother language is not English, so some of the skills are really hard to understand.
the thing is here:
I have got a assignment with 3 requirements:
1.Display the following:
The user’s username and the absolute path of the login directory;
The calendar of 2012;
The total number of files and subdirectories in your login directory;
Accept an input of a positive number N that is not greater than 45 (using the read command), and display the first N lines of the contents of Rail-Stations.txt.
The long listing of the directory specified by the first command line argument, sorted in reversed alphabetic order.
If the second command line argument is provided, all the above output will be redirected to the file specified by the second argument. If the second argument is not provided, the above output should be displayed on the screen. 2.Find the first letter in alphabet from the input and count the input letters:
Accept the input of a series of lower case alphabetic letters one at a time. The input ends with a 0. Find and display the first letter in alphabetic order and the count of total number of valid input letters. For example, input of d, g, t, w, q, b, h, d, s, 0 should result in b and 9.
Any invalid input character (eg. #, $, 3, A) will cause an error message and be ignored. 3.Exit the program
Before exit, ask user to confirm by entering a “Y” (“y”) or “N” (“n”). If confirmed, then exit, otherwise, return to the menu.
im stuck at the half way of the first requirement that is "display the first N lines of the contents of Rail-Stations.txt." then I can not continue any more. I tried to do the 3rd requirement, but i think its not gonna be right.
Somebody help me with it....im really up set, I tried to learn it by myself, but my bad English made this really hard...the best thing is to give me the code, I will learn from that
3. The attempts at a solution (include all code and scripts):
this is the code i did...maybe its gonna help a bit
Code:
#!/bin/sh
echo "This is your username:" $USER
echo "This is the path of your login directory:" $HOME
cal 2012
echo "The amount of files in your directory are:";(ls ~|wc -l)
read n
if[$n -lt 45];
then
head -n Rail-Stations.txt
fi
echo "Exit?(y/n)"
read e
if[e -eq 'y']&&[e -eq 'Y'];
then exit
if[e -eq 'n']&&[e -eq 'N'];
return
fi
fi
4. Complete Name of School (University), City (State), Country, Name of Professor, and Course Number (Link to Course):
UTS:insearch, Sydney, Australia, James Hu, IWBS001(web systems)
Moderator's Comments:
Code tags for code, please.
Last edited by Corona688; 04-16-2012 at 02:03 PM..
Consider [ ] to be commands, not brackets. if[$n is not the same command as [, the spaces are important.
You've left out lots of spaces everywhere and put in semicolons you don't actually need:
Code:
# wrong
if[$n -lt 45];
# right
if [ "$n" -lt 45 ]
You also forgot to use $e here, used the wrong logic(you want || for 'or', since a string can never be 'y' and 'Y' at the same time). Also, -eq is for integers, for strings you want = .
Code:
if [ "$e" = 'y' ] || [ "$e" = 'Y' ]
But I think that bit would be simpler as a case:
Code:
case "$e" in
[yY]) exit
;;
[nN]) return
;;
esac
Last edited by Corona688; 04-16-2012 at 02:14 PM..
Also, you need a loop for the menu since 'return' doesn't do what you think it does -- it quits the script just like exit does when used there.
Code:
REPLY="Y"
while [ "$REPLY" = "y" ] || [ "$REPLY" = "Y" ]
do
...
done
thx for your help, and what about the last 2 requirements in question one that is "The long listing of the directory specified by the first command line argument, sorted in reversed alphabetic order.
If the second command line argument is provided, all the above output will be redirected to the file specified by the second argument. If the second argument is not provided, the above output should be displayed on the screen. "and the 2nd question? I have no idea about these 2.
---------- Post updated at 03:33 AM ---------- Previous update was at 03:20 AM ----------
Quote:
Originally Posted by Corona688
Consider [ ] to be commands, not brackets. if[$n is not the same command as [, the spaces are important.
You've left out lots of spaces everywhere and put in semicolons you don't actually need:
Code:
# wrong
if[$n -lt 45];
# right
if [ "$n" -lt 45 ]
You also forgot to use $e here, used the wrong logic(you want || for 'or', since a string can never be 'y' and 'Y' at the same time). Also, -eq is for integers, for strings you want = .
Code:
if [ "$e" = 'y' ] || [ "$e" = 'Y' ]
But I think that bit would be simpler as a case:
Code:
case "$e" in
[yY]) exit
;;
[nN]) return
;;
esac
it shows "head:illegal line count -- Rail-Stations.txt"
and when I fix the 3rd part of the program,like this :
Code:
#!/bin/sh
echo "This is your username:" $USER
echo "This is the path of your login directory:" $HOME
cal 2012
echo "The amount of files in your directory are:";(ls ~|wc -l)
read n
if [ "$n" -lt 45 ];
then
head -n Rail-Stations.txt
fi
echo "Exit?(y/n)"
read e
if [ "$e" = 'y' ] || [ "$e" = 'Y' ];
then exit
if [ "$e" = 'n'] || [ "$e" = 'N' ];
return
fi
fi
it shows this :
Code:
Exit?(y/n)
y
./ass4: line 18: syntax error near unexpected token `fi'
./ass4: line 18: `fi'
Moderator's Comments:
code tags for code, please.
Last edited by Corona688; 04-16-2012 at 02:45 PM..
To keep the forums high quality for all users, please take the time to format your posts correctly.
First of all, use Code Tags when you post any code or data samples so others can easily read your code. You can easily do this by highlighting your code and then clicking on the # in the editing menu. (You can also type code tags [code] and [/code] by hand.)
Second, avoid adding color or different fonts and font size to your posts. Selective use of color to highlight a single word or phrase can be useful at times, but using color, in general, makes the forums harder to read, especially bright colors like red.
Third, be careful when you cut-and-paste, edit any odd characters and make sure all links are working property.
-n, --lines=[-]K
print the first K lines instead of the first 10; with the lead-
ing `-', print all but the last K lines of each file
So -n expects the number of lines. If you're not giving it a number of lines, don't bother telling head -n.
You're improperly nesting your if's. If you want to do if/else, use elif. Or you could break it into two completely separate if-statements. And you still have the useless ;'s there.
And the 'return' still doesn't do anything like what you think it does. It doesn't jump to the top of the script. To loop, you need a loop.
Code:
if [ "$e" = 'y' ] || [ "$e" = 'Y' ]
then exit
elif [ "$e" = 'n'] || [ "$e" = 'N' ]
return
fi # only one fi
The first argument is $1. So ls -l $1. There's another argument you can give ls to reverse its order, which you can find via man ls.
You can tell how many arguments there are with the $# special variable. Something like if [ "$#" -eq 2 ] to do one thing when you have two arguments, and another when you don't.
You can redirect into a file with >. command > filename
-n, --lines=[-]K
print the first K lines instead of the first 10; with the lead-
ing `-', print all but the last K lines of each file
So -n expects the number of lines. If you're not giving it a number of lines, don't bother telling head -n.
You're improperly nesting your if's. If you want to do if/else, use elif. Or you could break it into two completely separate if-statements. And you still have the useless ;'s there.
And the 'return' still doesn't do anything like what you think it does. It doesn't jump to the top of the script. To loop, you need a loop.
Code:
if [ "$e" = 'y' ] || [ "$e" = 'Y' ]
then exit
elif [ "$e" = 'n'] || [ "$e" = 'N' ]
return
fi # only one fi
The first argument is $1. So ls -l $1. There's another argument you can give ls to reverse its order, which you can find via man ls.
You can tell how many arguments there are with the $# special variable. Something like if [ "$#" -eq 2 ] to do one thing when you have two arguments, and another when you don't.
You can redirect into a file with >. command > filename
so
Code:
ls -l $1
is going to do this step?:
Code:
"The long listing of the directory specified by the first command line argument, sorted in reversed alphabetic order."
I dont know how to use
Code:
>
to redirecte all of this results above:
Code:
echo "This is your username:" $USER
echo "This is the path of your login directory:" $HOME
cal 2012
echo "The amount of files in your directory are:";(ls ~|wc -l)
read n
if [ "$n" -lt 45 ]
then
head -n Rail-Stations.txt
fi
to the 2nd argument, because it is in the program, its not like outside the program. i did
Code:
if [ "$# -eq 2 ]
and then what should I do?
also, what can I do with the 2nd question?:
Code:
Find the first letter in alphabet from the input and count the input letters:Accept the input of a series of lower case alphabetic letters one at a time. The input ends with a 0. Find and display the first letter in alphabetic order and the count of total number of valid input letters. For example, input of d, g, t, w, q, b, h, d, s, 0 should result in b and 9.Any invalid input character (eg. #, $, 3, A) will cause an error message and be ignored.
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04-16-2012
Need help with a really basic assignment, probably gonna take you 5 mins to do.but it worse 7% to me
