Use text file as a source of input

Question

Okay so basically I want to be able to use a text file with this format:

www.website.com 443 123.456.789.098
www.website2.com 443 765.432.101.234
....

as a source of input in which the script will take the website address and hold it in a variable and the same thing with the port and Ip address. So it would look like this:

website=www.website.com
port=443
ip=123.456.789.098

So far, I have tried this:

for line in [ cat $file_name ]; do
    website=`echo $line | cut -d" " -f1`
    port=`echo $line | cut -d" " -f2`
    ip=`echo $line | cut -d" " -f1`

But when i echo out the the variables all i get is this:

[
[
[

I can't seem to figure out how to go about solving this issue.

Aaron Digulla · Accepted Answer · 2012-07-03 12:50:56Z

3

Use this pattern instead:

while read line ; do
    ... loop body ...
done < "$file_name"

Explanation: for var in word-list will assign the words in the list to the variable in order. So for the first loop, $line will expand to [ (first word in the list). The next word would be cat and then the value of file_name.

To read from a file, you need to use I/O redirection.

while, on the other hand, will execute the command that you passed as argument (read line). read will read one line from stdin and put the value into the variable that you passed as argument.

The odd done < $file_name sets the stdin for read. And to make you life even more simple, you can use read to split the input for you:

while read website port id ; do
    ...

edited Jul 3, 2012 at 12:50

answered Jul 3, 2012 at 12:45

Aaron Digulla

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mbonnin · Accepted Answer · 2012-07-03 13:23:19Z

3

for does not read line by line by default but reads tokens delimited by $IFS. By default, IFS usually contains space, tab and newline. If you want to force bash to read line by line (and not whitespace separated tokens), you can do so with:

IFS=`echo -ne '"\n"'`; for line in `cat $file`; do echo $line; done

Note the backticks around cat $file that will execute the cat 'inline'.

Using read is another alternative. Certainly more easy to read and understand than changing the IFS (Internal Field Separator)

edited Jul 3, 2012 at 13:23

answered Jul 3, 2012 at 13:03

mbonnin

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rush · Accepted Answer · 2012-07-03 12:50:55Z

2

while read WEBSITE PORT IP
do 
    echo $WEBSITE $IP $PORT ; 
done < file

But you won't be able to use this variables after the cycle has finished.

answered Jul 3, 2012 at 12:50

rush

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