UNIX for Dummies Questions & Answers

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Can please someone help me
First is this correct: while [ $string != "" ] how we symbolise space? I mean is "" correct?


and this var=`cut -f1 -d\"" $string` how we symbolise the space or blank character here? Is this -d\"" or -d " " correct. Because all them are wrong

If there is no space between the quotation marks then it's the empty string, with no characters in it.

To symbolize a space, put a space between the quotation marks.

You can play with "echo" and "cat -A" to see what happens. (Your cat might use a slightly different option character.)

Code:

vnix$ echo "" | cat -A
$
vnix$ echo " " | cat -A
 $

The $ shows the end of line, so you can tell whether or not there was any whitespace. Or just put something around it:

Code:

vnix$ echo ."".
..
vnix$ echo ." ".
. .

\" means a literal double quote, so -d \"" is a syntax error (literal double quote followed by opening string quote, but no closing string quote). -d " " with a space between should work; doesn't it work for you? Backslash followed by space (-d \ )should also work, without any quote marks at all.

So how we symbolise the end of line in:
while [ $seira != "" ] . seira is a string that has blank spaces between the characters. I want to read it with while until end of line. how we symbolise it? Is the above correct

What do you mean by "read it with while"? You need to show more of your code.

The above says "while $seira is not an empty string" so that seems vaguely like what you're after. (You should have double quotes around $seira though.)

I have a file that has dates like this:
date FINAL_RESULT; 6
date FINAL_RESULT; 3
date FINAL_RESULT; 8

With this command: seira=`cut -f2 -d\; tes.txt` i take the date FINAL RESULTs and i store them on variable seira.then seira look like this: 6 3 8
I want to read seira and make a sum of all results 6+3+8 etc. i don't know how mane records there are in the file. So i want to read seira with the the next loop using while but it doesn 't work. i don't want to use grep or awk. I want to use while and cut but it is wrong. Can yoy help me please

while [ "$seira" != "" -a "$seira" != " " ]
do
sum=0
pros1=`cut -f1 -d \ $seira`
pros2=`cut -f2 -d \" " $seira`
sum=`expr $sum+$pros1`
seira=$pros2
done

I hope you haven't forgotten me, because i am in a big need right know

Here is my liitle code. I hope this help. But i am also a beginner in shell scripting. I thought i will just give it a try!

I have the text in file bb

/home/gkalangi$ cat bb
date FINAL_RESULT; 6
date FINAL_RESULT; 3
date FINAL_RESULT; 8

the script to find the sum:

#!/bin/sh

seira=`cut -d\; -f2 bb`
echo $seira
sum=0

for num in `echo $seira`
do
sum=`expr $sum + $num`
done

echo $sum

Please let me know if it helped you!