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Old 02-01-2008, 01:39 AM   #1
sharath.bv
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Registered: Jan 2008
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"How to read lines from a file"


Hi,

I want to read lines from a file line-by-line and to display those lines on the terminal.
Can any one please provide a shell script for this.
 
Old 02-01-2008, 01:49 AM   #2
lazlow
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cat filename | more -1
The "|" is the pipe sysmbol (shift \ on my keyboard).
 
Old 02-01-2008, 01:55 AM   #3
eoo
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Registered: Nov 2003
Distribution: SuSE 8.1
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Hi,

I'm not sure what you're trying to do, but I'd use sed, e.g.

Quote:
sed -n "${i}p" $file
A longer longer example would be something like

Quote:
#! /bin/bash

file=/etc/fstab
nlines=$(wc -l $file | cut -f1 -d' ')
i=0

while [ $i -le $nlines ]
do
echo "Give me a line number"
read i
sed -n "${i}p" $file
done

echo "Reached end"
Hope this helps

Cheers
 
Old 02-01-2008, 02:34 AM   #4
Disillusionist
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Quote:
Originally Posted by sharath.bv View Post
Hi,

I want to read lines from a file line-by-line and to display those lines on the terminal.
Can any one please provide a shell script for this.
This is obviously just a starting point, so please forgive me for asking.

What are you trying to achieve?

To read each line into a variable you could do:
Code:
#!/bin/bash
cat myfile|while read line
do
   ##perform some checks
   echo $line
done
However, this strips out any leading spaces or tab characters, therefore you may not get what you are after.

To do the same thing in Perl (which doesn't strip out leading spaces or tab characters):
Code:
#!/usr/bin/perl
open(INPUT, "myfile") or die "Could not open input file";

while (<INPUT>) {
   ##perform some checks
   print;
}

close(INPUT);
 
Old 02-01-2008, 03:41 AM   #5
sharath.bv
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Registered: Jan 2008
Posts: 17

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Thanks

Thanks all,
i got the answer.........
 
Old 02-01-2008, 07:47 AM   #6
H_TeXMeX_H
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The simplest and most readable way is (IMO):
Code:
while read line
do
  echo $line
done < file

Last edited by H_TeXMeX_H; 02-01-2008 at 07:52 AM.
 
  


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