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Why does my script only read two lines of a file and not the third

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Top Forums Shell Programming and Scripting Why does my script only read two lines of a file and not the third
# 1  
Old 01-30-2011
Why does my script only read two lines of a file and not the third
I'm learning about the read command and wrote this little script to read data from a file:
Code:
readfile()
{
 while read variable; do
echo $variable
done
}    
readfile < File.txt

I have three lines in File.txt; each a single word. The script only echoes the first two lines and drops the third one. Can anyone tell me why?

Also, what does the statment

if [ $variable ] mean? Does it mean 'if the value of variable exists....'?
# 2  
Old 01-30-2011
can you post your File.txt?This code runs okay on my laptop.
I think [ $variable ] means to test if the value of variable is null or unset,if so,evaluated as false.use [ -n $variable ] or [ -z $variable ] will be better.
# 3  
Old 01-30-2011
Sure can. Here is the file -- only three lines

Red
Blue
Green

It echoes Red and Blue but not green. Did it return all the lines in your file?
# 4  
Old 01-30-2011
--Works fine for me too:

Code:
$ cat testit
readfile()
{
  while read variable; do
echo $variable
done
}
readfile < File.txt
$ cat File.txt
one
two
three
$ ./testit
one
two
three

if [$variable ] wont work as intended when $variable contains a space eg variable="one two", best to stick with:
Code:
if [ -n "$variable" ]

# 5  
Old 01-30-2011
Never mind -- figured it out, although I feel like an idiot. Smilie

I saved the file without hitting return after the last word. Out of curiosity, can anyone tell me why that is?
Runs fine now.
# 6  
Old 01-30-2011
Quote:
Originally Posted by Straitsfan
I saved the file without hitting return after the last word. Out of curiosity, can anyone tell me why that is?
Runs fine now.
Smilie,interesting~Even without hitting return,i get three lines and if i hit return,it will print a blank line as expected.
# 7  
Old 01-30-2011
read returns a non-zero if it encounters a END-OF-FILE char and zero if it encounters a CR char. variables are populated with anything that is read to this point.

You should probably do something like:

Code:
readfile()
{
  while read variable; do
    echo "$variable"
  done
  echo -e "${variable}\c"
}
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