This content originally appeared on DEV Community and was authored by Bartosz Gordon
This is the shopping.csv CSV file that we will be working with throughout this blog post.
item,price
rice,2.49
potatos,1.49
pasta,3.79
The goal is to create a one-line bash script that prints the sum of the prices in the file above, which is 7.77.
Step: 1. Print the file content
$ cat shopping.csv
This command prints the file content without modifications.
It gives us a way to redirect - pipe - the output to another command in the next step.
Output:
item,price
rice,2.49
potatos,1.49
pasta,3.79
Step: 2. Cut the first line
There are many ways to achieve it, but we use the tail +n syntax.
In our case, it takes all the lines until the end of the file, starting from the second line.
$ cat shopping.csv | tail +2
Output:
rice,2.49
potatos,1.49
pasta,3.79
Step: 3. Cut the first column
awk splits each line by a separator defined by the option -F.
In our case, it's the comma.
Then it prints the second column from every row.
$ cat shopping.csv | tail +2 | awk -F , '{print $2}'
Output:
2.49
1.49
3.79
Step: 4. Concatenate the prices
xargs is used to "squash" the lines into a single string, separating them by space.
$ cat shopping.csv | tail +2 | awk -F , '{print $2}' | xargs
Output:
2.49 1.49 3.79
Step: 5. Replace spaces with pluses
The sed expression replaces the escaped space with + in the entire string (globally - g).
$ cat shopping.csv | tail +2 | awk -F , '{print $2}' | xargs | sed -e 's/\ /+/g'
Output:
2.49+1.49+3.79
Step: 6. Perform the calculation
bc is a simple calculator that you can use interactively or by piping an equation into it.
$ cat shopping.csv | tail +2 | awk -F , '{print $2}' | xargs | sed -e 's/\ /+/g' | bc
Output:
7.77
This content originally appeared on DEV Community and was authored by Bartosz Gordon
Bartosz Gordon | Sciencx (2021-06-07T20:18:03+00:00) One-liner to sum up numbers from a CSV file. Retrieved from https://www.scien.cx/2021/06/07/one-liner-to-sum-up-numbers-from-a-csv-file/
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