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This article will show you multiple ways to sum a list of numbers in a file using Bash scripts. The first method involves using the paste command, and we will discuss two cases: using an existing file and reading a file using standard input.

cutFinally, we'll discuss the and commands for obtaining sums awk.

Sum a list of numbers in a text file using Bash

The method described below will assume that we have an input file titled numbers.txt.

numbers.txt file:

1
2
3
4
5
6
7
8
9
10

Use existing file

If we store all the numbers in a simple text file with each number on a separate line, then we can call the following command in Bash and get the sum.

Order:

paste -sd+ numbers.txt | bc

Output:

55

Using standard input (stdin)

The following command can read from a file and get the sum of the numbers.

Order:

cat numbers.txt | paste -sd+ | bc

Output:

55

In this case, we use the command cat numbers.txt to read from the file. This command can be replaced with any other command that returns a list of numbers.

It should be noted that while paste has a POSIX-defined specification, not every implementation is the same. The following command would need to be used on Mac OS to get the same output.

Order:

<cmd> | paste -sd+ - | bc

Using the cut command

Suppose we have a text file with multiple columns and we want to get the sum of a particular column. We can use the cut command to achieve this.

Suppose we have a numbers.txt file with the following definition:

1 1
2 1
3 1
4 1
5 1
6 1
7 1
8 1
9 1
10 1

We can summarize each column individually using the following command.

Order:

cat numbers.txt | cut -d ' ' -f 2 | paste -sd+ | bc -l

-fThe following parameter indicates the column number to be summed. Note also that in this case, the column numbers are counted starting at 1 instead of 0.

When we -fadd the passed 2 flag, we get the sum of the second column.

Output:

10

Using awk command

The awk command, named after its author, is much better suited to this task than our previous approach. When measured, awk performs much better than our previous approach.

Order:

awk '{s+=$1} END {print s}' numbers.txt

Output:

55

You can replace numbers.txt with the name of the file containing your numbers. This also allows us to bypass reading the file through cat, which is partly responsible for the excellent performance.