How do I break up an extremely long string literal in bash?

Question

I would like to embed a long command like this in a bash script:

mycommand \\
    --server myserver \\
    --filename extremely/long/file/name/that/i/would/like/         


        

Answer 1

I define a short strcat function at the top of my bash script and use an inline invocation to split things up. I sometimes prefer it to using a separate variable because I can define the long literal in-line with the command invocation.

function strcat() {
  local IFS=""
  echo -n "$*"
}

mycommand \
  --server myserver \
  --filename "$(strcat \
      extremely/long/file/name/ \
      that/i/would/like/to/be/able/to/break/ \
      up/if/possible)" \
  --otherflag \
  --anotherflag \

I also like this approach for when I have to enter a long CSV of values as a flag parameter because I can use it to avoid typing the comma between values:

function strjoin() {
  local IFS="$1"
  shift
  echo -n "$*"
}

csv_args=(
  foo=hello
  bar=world
  "this=arg  has  spaces  in  it"
)
mycommand \
  --server myserver \
  --csv_args "$(strjoin , "${csv_args[@]}")" \
  --otherflag \
  --anotherflag \

Which is equivalent to

mycommand \
  --server myserver \
  --csv_args "foo=hello,bar=world,this=arg  has  spaces  in  it" \
  --otherflag \
  --anotherflag \