shell script construct array for file elements

Question

I have a file named input_file which contains some lines. I need to remove certain characters in the line and store them in an array. So to remove the characters, I use the sed command and storing in a variable as below.

 all_values=$(sed 's/^[^.]*\. //' < input_file) echo "$all_values" 

It is working perfectly fine but I need all_values to be an array so that all_values[0] will contain the first line and all_values[1] the second line and so on.

Since I have a file, I do not know the total array elements before hand. How can I construct an array for my case?

EDIT:

My input file is like below.

This is first element This is second element Though spaces, I should be one element 

Answer 1

You just need a bit more syntax to store the output in an array

all_values=( $(sed 's/^[^.]*\. //' < input_file) ) 

There will be trouble if any of the lines of output contain whitespace: each whitespace separated word will be a separate array element. Please show some sample input if that's the case.

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all_values=() while read -r line; do all_values+=( "$line" ) done < <( sed 's/^[^.]*\. //' input_file ) 

Or, more tersely

mapfile -t all_values < <( sed 's/^[^.]*\. //' input_file ) 

mapfile is a bash built-in: see help mapfile from a bash prompt.

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You don't even need sed for this. If I read your intention is to remove the first sentence from each line:

$ cat input_file Ignore me. keep me Don't want this. Do want this $ mapfile -t a < input_file $ shopt -s extglob $ a=( "${a[@]#*([^.]). }" ) $ printf "%s\n" "${a[@]}" keep me Do want this