Fish shell tips - a work in progress

batch_convert_HEIC.md

Batch convert HEIC using a fish shell

for p in *.HEIC;
  heif-convert $p (path change-extension jpg $p)
end

Note the path command required fish 3.5

fish shell tips.md

Command subsitution

set var1 (pwd)
echo $var1

A command substitution can have a dollar sign before the opening parenthesis like outercommand $(innercommand). This variant is also allowed inside double quotes. When using double quotes, the command output is not split up by lines.

For example,

second line" > myfile
set myfile "$(cat myfile)"
printf $myfile

prints

first line
second line⏎

without the double quotes this is first line second line

Between single quotes, fish performs no expansions. Between double quotes, fish only performs variable expansion.