TL, DR:
array_of_lines=("${(@f)$(my_command)}")
First mistake (→ Q2): IFS='\n' sets IFS to the two characters \ and n. To set IFS to a newline, use IFS=$'\n'.
Second mistake: to set a variable to an array value, you need parentheses around the elements: array_of_lines=(foo bar).
This would work, except that it strips empty lines, because consecutive whitespace counts as a single separator:
IFS=$'\n' array_of_lines=($(my_command))
You can retain the empty lines except at the very end by doubling the whitespace character in IFS:
IFS=$'\n\n' array_of_lines=($(my_command))
To keep trailing empty lines as well, you'd have to add something to the command's output, because this happens in the command substitution itself, not from parsing it.
IFS=$'\n\n' array_of_lines=($(my_command; echo .)); unset 'array_of_lines[-1]'
(assuming the output of my_command doesn't end in a non-delimited line; also note that you lose the exit status of my_command)
Note that all the snippets above leave IFS with its non-default value, so they may mess up subsequent code. To keep the setting of IFS local, put the whole thing into a function where you declare IFS local (here also taking care of preserving the command's exit status):
collect_lines() {
local IFS=$'\n\n' ret
array_of_lines=($("$@"; ret=$?; echo .; exit $ret))
ret=$?
unset 'array_of_lines[-1]'
return $ret
}
collect_lines my_command
But I recommend not to mess with IFS; instead, use the f expansion flag to split on newlines (→ Q1):
array_of_lines=("${(@f)$(my_command)}")
Or to preserve trailing empty lines:
array_of_lines=("${(@f)$(my_command; echo .)}")
unset 'array_of_lines[-1]'
The value of IFS doesn't matter there. I suspect that you used a command that splits on IFS to print $array_of_lines in your tests (→ Q3).
I think you are looking for :- parameter substitution:
$ restofarglist='abc,def'
$ echo ${(s/,/)${:-arg1,arg2,$restofarglist}}
arg1 arg2 abc def
From man zsh:
${name:-word}
If name is set, or in the second form is non-null, then substitute its value;
otherwise substitute word. In the second form name may be omitted, in which
case word is always substituted.
Actually you can make this example a little bit shorter:
$ echo ${${:-arg1,arg2,$restofarglist}//,/ }
arg1 arg2 abc def
Best Answer
Use
$^array.It turns the array into a sort of brace expansion of the array. As in when
a=(foo bar baz),$^awould be a bit like{foo,bar,baz}.For multiplexing arrays:
Naturally, if the prefix or suffix contain shell special characters (like
;that separates commands or space that separate words, or$"'&*[?~...), they must be quoted:same as for
csh's (and bash, ksh, zsh's):$^aitself must not be quoted,"foo${^a}bar"would expand as one word. One case where you would want$^arrayto be quoted, the same as for$arrayis when you want to preserve empty elements. Then, you need to quote the array expansion and use the(@)flag or the"${array[@]}"syntax (reminiscent of the Bourne shell's"$@"):