On Mon, 2 Feb 2026, Greg Wooledge wrote: > On Tue, Feb 03, 2026 at 01:19:35 +0000, [email protected] wrote: >> On Mon, 2 Feb 2026, Greg Wooledge wrote: >> >>> On Mon, Feb 02, 2026 at 23:30:16 +0000, [email protected] wrote: >>>> don't know what he meant >>>> https://stackoverflow.com/questions/7578930/bash-split-string-into-character-array >>> >>> Oh, so you didn't actually WRITE the code. >>> >>> Was your question "How does this code work?" >> >> yes > > OK, here's the code once again: > > string='whatever' > [[ $string =~ ${string//?/(.)} ]] > array=( "${BASH_REMATCH[@]:1}" ) > > The first line is just assigning the input, which in a real script > would come from somewhere other than the script itself. > > The second line is really doing two things. It's been written as a > single line for brevity. Let's break it apart: > > re=${string//?/(.)} > [[ $string =~ $re ]] > > I've inserted the temporary variable "re" here, to hold a regular > expression. This is the real magic. "re" contains a regexp which > has one instance of "(.)" for every character in the input string. > For example, if the input string has 8 characters, the re has 24. > > hobbit:~$ string='whatever' > hobbit:~$ re=${string//?/(.)} > hobbit:~$ declare -p re > declare -- re="(.)(.)(.)(.)(.)(.)(.)(.)" > > The [[ command with =~ operator matches a string (the left hand side) > against an Extended Regular Expression (the right hand side). > > [[ $string =~ $re ]] > > expands to > > [[ whatever =~ (.)(.)(.)(.)(.)(.)(.)(.) ]] > > Each (.) is a single-character wildcard match with parentheses around it, > meaning it's captured as a substring. The first (.) captures the w, > the second captures the h, the third captures the a, and so on. > > After a [[ command with =~ operator has completed, the BASH_REMATCH > array will be populated with the substring that matched the full > regular expression (index 0), and then each captured substring > (index 1 and beyond). > > hobbit:~$ [[ $string =~ $re ]] > hobbit:~$ declare -p BASH_REMATCH > declare -a BASH_REMATCH=([0]="whatever" [1]="w" [2]="h" [3]="a" [4]="t" > [5]="e" [6]="v" [7]="e" [8]="r") > > Finally, we have > > array=( "${BASH_REMATCH[@]:1}" ) > > which simply copies the elements of the BASH_REMATCH array starting > at index 1 into the output array variable. > > hobbit:~$ array=( "${BASH_REMATCH[@]:1}" ) > hobbit:~$ declare -p array > declare -a array=([0]="w" [1]="h" [2]="a" [3]="t" [4]="e" [5]="v" [6]="e" > [7]="r") >
a feast for thought thanks
