Hi everyone,
I ran into the following problem: I want to pass the result of one command
as the parameter of another command. Normally command substitution is the
way to go but if the output contains newlines, I want to pass them verbatim.
In all the ways I tried fish splits the output into multiple arguments.
My use case:
notify-send "Program crashed!" (grep ! logfile)
Try
count (echo 1\n2\n3) ==> 3
I want some way to make that expand into
count 1\n2\n3
instead of
count 1 2 3
AFAIK fish has no syntax to say "use the result of this command as a single
argument". Did I miss anything on this?
It's possible to manually use a loop to stitch the command result back
together again, but the result cannot be returned from a function, because
then it will be split up again. So it's hard to abstract such functionality.
I worked around this using the following function:
function strjoin --description '\n-safe string join function; output in
$<first arg>'
set -l var $argv[1]
set -l sep $argv[2]
if [ (count $argv) -ge 3 ]
set $var $argv[3]
end
for i in (seq 4 (count $argv))
set $var {$$var}$sep$argv[$i]
end
end
use as:
set -g logentries #make empty global variable
strjoin logentries \n (grep ! logfile)
notify-send "Program crashed!" $logentries
But this is still ugly, requires several lines to use instead of a simple
command substitution, and uses additional global variables with the risk of
variables clashing.
FWIW, bash handles this better, it allows command substitution in a double
quoted string, resulting in a single argument. One option for fish syntax
would be to allow
notify-send "Program crashed!" "(grep ! logfile)"
I think that would be the nicest, and it's analogous to the "$a" syntax for
making an array expand into a single argument.
So:
- Is there syntax that I missed that does this?
- If not, do we need any? I think it is an important feature to be able to
handle special characters in any output
- What kind of syntax would do?
Jan
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