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Full Discussion: While read
Top Forums Shell Programming and Scripting While read Post 303014117 by Ghassen on Monday 5th of March 2018 12:15:31 PM
Old 03-05-2018
While read
Hello from Paris,

Here is a script that i wrote. I nammed this script sum.sh :

Code:
#! /bin/bash

sum=0
cat $1 | while read line
do
#set $line
sum=`expr $sum  +  1`
done
echo $sum

When I execute this script with a 4 lines file as argument, it returns 0 and not 4 as i expected :

Quote:
ghassen@ghassen-Lenovo-V110-15ISK:~/Bash$ cat fic
line 1
line 2
line 3
line 4
ghassen@ghassen-Lenovo-V110-15ISK:~/Bash$ ./sum.sh fic
0
ghassen@ghassen-Lenovo-V110-15ISK:
Somebody could explain to me why and how i can change this script to get 4 as return ?

Thank you !
 

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LEARN ABOUT DEBIAN

getcol

getcol(1)						      General Commands Manual							 getcol(1)

Name
       getcol - Extract specified columns from an ASCII table file

Synopsis
       getcol [-amv][-n num][-r lines][-s num] filename [column number range]

Description
       Extract specified columns from an ASCII table file

Options
       filename
	      Name  of a ASCII table file.  At least one of these must be present for any values to be printed.  If it is stdin or STDIN, an ASCII
	      table is expected as standard input.  If there is no input file, standard input is assumed.

       @filename
	      Name of a file containing a list of ASCII table files.  If this is present, any other  file  names  on  the  command  line  will	be
	      ignored.

       field range
	      Print  value  of	these  columns for the number of lines of the table specified by the -n argument after the skippiing the number of
	      lines specified by the -s argument.  A value of 0 causes the entire input line to be printed.

       -a     Sum all numeric columns selected, printing the sum on the line following the result.  Columns with  no  sum  are	filled	with  ___.
	      (Added in version 2.6.9)

       -b     Input is bar-separate table file

       -c     Add count of number of lines in each column at end

       -d <number>
	      Number of decimal places in f.p. output

       -e     Compute medians of selected columns

       -f     Print range of values in selected columns

       -h     Print Starbase tab table header

       -i     Input is tab-separate table file

       -k     Print number of columns on first line

       -l <number>
	      Number of lines to add to each line

       -m     Compute the means of all numeric columns selected, printing the mean on the line following the result (or the line following the sum
	      if -a is used).  Columns with no mean are filled with ___.  (Added in version 2.6.9)

       -n num Print selected columns for this many lines.  If not specified, all lines will be read after the number of lines specified by -s have
	      been skipped.

       -o     OR conditions insted of ANDing them

       -p     Print only sum, mmean, sigma, median, or range, not entries

       -r @listfile
	      -r  line	range  Print  columns from the lines specified as either the first nonzero number on each line of the file listfile or the
	      comma- and hyphen- delimitied range; i.e. 1-5,10-12 will print values from lines 1, 2, 3, 4, 5, 10, 11, and 12.  (added  in  version
	      2.6.12)

       -s num Skip this many line before starting to print values.  If not specified, no lines will be skipped.

       -t     Starbase (tab-separated) table output

       -v     Print more information about process.

       Web Page
	      http://tdc-www.harvard.edu/software/wcstools/getcol.html

Author
       Doug Mink, SAO (dmink@cfa.harvard.edu)

8 November 2001 						     WCSTools								 getcol(1)
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