Linux Blog

Using wc and How To Count Table Rows

Filed under: Shell Script Sundays — TheLinuxBlog.com at 1:07 pm on Sunday, March 9, 2008

I made this little script to check how many packages were available on the web from the Cygwin Package Repository located at http://www.cygwin.com/packages

Its a one liner but it does its job well.

CYGLIST=$(curl http://www.cygwin.com/packages/ | grep \<tr | grep ball | wc -l); echo $CYGLIST;

All the above is doing is creating a variable called CYGLIST that is the result of grabbing the cygwin.com/packages/ page, grepping all of the TR’s that also have the word “ball” in it (for the image) and then using the wc -l (L) command to count how many results are found. Then the list is echoed out.

wc is a very useful command for printing newline, word and byte counts. This is a good example of how to use wc to count lines in a shell script. wc can also be used to print all of these values in one line of a file.  The syntax is below:

<p align="left">bash-3.1# wc file.txt
9  20 184 file.txt

The above shows the number of lines in the file.txt, it shows how many words are in the file and also how many bytes. In my first example wc uses the -l switch to display the number of lines. This script can also be used with a little bit of bash math to calculate how many items are in an HTML list. I’m working on a script that automatically does this, when its finished I will be sure to post it here on The Linux Blog.

Man Pages for commands in this post »

wc
curl
grep
echo

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