Shell Programming and Scripting

Hi all,
I haven't needed to do any shell based editing for nearly 20 years, and no amount of searching around has found me a solution to this very simple problem :-(

I have a csv file.
Some lines have three commas at the end. This means the invoice hasn't been paid.
I'd like to use sed / grep etc to create a new file with just the lines which have the three trailing commas, deleting (just) the trailing commas in the process.

What I've done is this:

Code:

#Firsty, get all invoices which have been paid, and save them to this folder 
grep -v ,,, Invoices.csv > Invoices_Paid.csv

#Then, get the ones which haven't been paid (identified by three commas at the end of the line) and save them to this folder
grep ,,, Invoices.csv > Invoices_Unpaid.csv

The bit that's missing is the removal of just the trailing commas from the Unpaid Invoices line. Can anyone help?

many thanks

(Very rusty) James

Moderator's Comments:

Try using code tags instead of icode tags

Here is an awk program to identify lines that has 3 trailing commas, delete them and print:

Code:

awk '/,,,$/{sub(/,,,$/,x); print}' filename

With sed:

Code:

sed -n 's/,,,$//p' file

Be aware that your pattern will match even if the three commas are not at the end of the line. If that's a possibility, you need to anchor your match to the end of the line using ,,,$. Even if it's not a possibility at this time, the explicit anchor serves as documentation and future-proofing.

In my opinion, sed is probably the best fit for the job:

Code:

sed -n 's/,,,$//p'

Regards,
Alister

many thanks :-)