Parsing files

krishna.reddy · #1 (**permalink**) 04-07-07, 19:46

Hi,

I need to read the file, line by line and do some parsing on them and then write the line into some other file.

But the problem is, if file_one has a new line, below logic will not work. I'm getting only half of file_one into file_two.

Any ideas? Is there anything like 'EOF' in Shell for reading the file till the end?

echo "`cat $file_name`" | while read tmp_line
do
cc=`echo "$tmp_line" | wc -w`
# ^^^^^^^^^^^^^^^ ----->cc will get 0 if tmp_line is a new line.
if [ $cc -lt 1 ]
then
echo "File $file_name has been read." >> $LOG_FILE
break;
else
echo "$file_name $tmp_line" >> $FILE_TWO
fi
done

Tyveleyn · #2 (**permalink**) 04-08-07, 05:20

Hi,

In:

Code:

echo "`cat $file_name`" | while read tmp_line
do
    cc=`echo "$tmp_line" | wc -w`
    if [ $cc -lt 1 ]
    then
        echo "File $file_name has been read." >> $LOG_FILE
        break;
    else
        echo "$file_name $tmp_line" >> $FILE_TWO
    fi
done

the 'break' command causes the while loop to terminate definitively so with every empty inputline the reading stops. The reading of the complete file is already controlled by 'while read tmp_line' which returns false when there's no line left to be read and thus terminates the loop automatically.

Regards

Damian Ibbotson · #3 (**permalink**) 04-19-07, 15:29

Am I missing something here?

while read will continue reading until the read returns a non-zero exit status, i.e. when there are no more lines to read.

I'd do away with needless cat and temporary variable assignments too.

Code:

while read line
do
    # do your parsing here, e.g.
    echo "$line"

done < yourInputFile >> yourOutputFile

Tyveleyn · #4 (**permalink**) 04-20-07, 04:02

Krisna asked

Quote:

Any ideas? Is there anything like 'EOF' in Shell for reading the file till the end?

not to rewrite his script. That's what you were missing...

Regards

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