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Using readarray in the bash shell, and GNU sed:

readarray -t my_array < <( my_command | sed -n '2~2p' )

The built-in readarray reads the lines into an array. The lines are read from a process substitution. The sed command in the process substitution will only output every second line read from my_command (and could also be written sed '1!n;d', or as sed -n 'n;p' with standard sed).

In GNU sed, the address n~m addresses every m:th line starting at line n. This is a GNU extension to standard sed.

The my_command command will only ever be called once.

Testing:

$ readarray -t my_array < <( seq 10 | sed '1~2d' )

$ printf '%s\n' "${my_array[@]}"
2
4
6
8
10

Using readarray in the bash shell, and GNU sed:

readarray -t my_array < <( my_command | sed '1~2d' )

The built-in readarray reads the lines into an array. The lines are read from a process substitution. The sed command in the process substitution will only output every second line read from my_command (and could also be written sed '1!n;d', or as sed -n 'n;p' with standard sed).

In GNU sed, the address n~m addresses every m:th line starting at line n. This is a GNU extension to standard sed, for convenience.

The my_command command will only ever be called once.

Testing:

$ readarray -t my_array < <( seq 10 | sed '1~2d' )

$ printf '%s\n' "${my_array[@]}"
2
4
6
8
10

Using readarray in the bash shell, and GNU sed:

readarray -t my_array < <( my_command | sed -n '2~2p' )

The built-in readarray reads the lines into an array. The lines are read from a process substitution. The sed command in the process substitution will only output every second line read from my_command (and could also be written sed '1~2d', or as sed -n 'n;p' with standard sed).

In GNU sed, the address n~m addresses every m:th line starting at line n. This is a GNU extension to standard sed.

The my_command command will only ever be called once.

Testing:

$ readarray -t my_array < <( seq 10 | sed '1~2d' )

$ printf '%s\n' "${my_array[@]}"
2
4
6
8
10

Using readarray in the bash shell, and GNU sed:

readarray -t my_array < <( my_command | sed -n '2~2p' )

The built-in readarray reads the lines into an array. The lines are read from a process substitution. The sed command in the process substitution will only output every second line read from my_command (and could also be written sed '1!n;d', or as sed -n 'n;p' with standard sed).

In GNU sed, the address n~m addresses every m:th line starting at line n. This is a GNU extension to standard sed.

The my_command command will only ever be called once.

Testing:

$ readarray -t my_array < <( seq 10 | sed '1~2d' )

$ printf '%s\n' "${my_array[@]}"
2
4
6
8
10

Using readarray in the bash shell, and GNU sed:

readarray -t my_array < <( my_command | sed -n '2~2p' )

The built-in readarray reads the lines into an array. The lines are read from a process substitution. The sed command in the process substitution will only output every second line read from my_command (and could also be written sed '1~2d').

In GNU sed, the address n~m addresses every m:th line starting at line n. This is a GNU extension to standard sed.

The my_command command will only ever be called once.

Testing:

$ readarray -t my_array < <( seq 10 | sed '1~2d' )

$ printf '%s\n' "${my_array[@]}"
2
4
6
8
10

Using readarray in the bash shell, and GNU sed:

readarray -t my_array < <( my_command | sed -n '2~2p' )

The built-in readarray reads the lines into an array. The lines are read from a process substitution. The sed command in the process substitution will only output every second line read from my_command (and could also be written sed '1~2d', or as sed -n 'n;p' with standard sed).

In GNU sed, the address n~m addresses every m:th line starting at line n. This is a GNU extension to standard sed.

The my_command command will only ever be called once.

Testing:

$ readarray -t my_array < <( seq 10 | sed '1~2d' )

$ printf '%s\n' "${my_array[@]}"
2
4
6
8
10