Shell Programming and Scripting

a sed one

Code:

$ sed -n '$=' <filename>

Code:

wc -l compare_output.dat | cut -d " " -f 1

wc -l [filename] | awk '{print $1}'

replacing [filename] with the name of the file the output will give you the line count.

Hope that helps

I'm having a similar problem. I'm trying to assign the results of a line count to a variable so it can be used in an arithmetic expression which in turn will split a document in half (on the basis of the a halved line count). No such luck. Any hints?

The output from "wc" usually has some embedded whitespace, which can prevent the shell from treating it like a number:

Code:

# num=$(wc -l < /etc/hosts)
# echo "NUM='$num'"        
NUM='    1605'        # whoops!

# ((num=$(wc -l < /etc/hosts)))
# echo "NUM='$num'"
NUM='1605'            # that's better

Of course, there are other ways to get the number:

Code:

# wc -l /etc/hosts | read num garbage
# num=$(awk 'END{print NR}' /etc/hosts)
# num=$(grep -c . /etc/hosts)      # this excludes blank lines!

Choose your poison.

Here's a stab at it.

==========Script follows ===========
#!/bin/ksh
filename=$1
tline=$(wc -l $filename | awk '{print $1}')
let hline=$tline/2
split -l $hline $filename
=========== End of script ==========

This will output 2 files, call xaa and xab by default, check the man page for split to see how to make it what you want.

Syntax to execute it is scriptname [file_to_be_split]

Variable definitions
filename - file to be split
tline - number of lines in the file
hline - 1/2 of the number of lines in the file

Hope this helps, sure there are other ways.

I'd modify olenkline's script slightly ... mainly because an odd value of hline would have split the file into three pieces!

==========Script follows ===========
#!/bin/ksh
filename=$1
tline=$(wc -l $filename | awk '{print $1}')
hline=$(((1+tline)/2))
split -l $hline $filename
=========== End of script ==========

numerous other ways to add the one so that hline=7 (rather than 6) when tline=13