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

Another way of writing a long string to a variable while keeping the maximum line length at bay:

printf -v fname '%s' \
    'extremely/long/file/name/that/i/' \
    'would/like/to/be/able/to/break/up/' \
    'if/possible'

Because there are more arguments than formatting directives, %s is just repeated and we get

$ declare -p fname
declare -- fname="extremely/long/file/name/that/i/would/like/to/be/able/to/break/up/if/possible"

which an be used like

mycommand \
    --server myserver \
    --filename "$fname" \
    --otherflag \
    --anotherflag

This is extra handy when setting long variables with inherently separated contents such as CDPATH (or PATH, of course):

printf -v CDPATH '%s' \
    ':/Users/benjamin/here/is/a/long/path' \
    ':/Users/benjamin/and/here/is/another/one' \
    ':/Users/benjamin/and/a/third/line'
export CDPATH

as opposed to

export CDPATH=':/Users/benjamin/here/is/a/long/path:/Users/benjamin/and/here/is/another/one:/Users/benjamin/and/a/third/line'

or the clunky

export CDPATH=':/Users/benjamin/here/is/a/long/path'
CDPATH+=':/Users/benjamin/and/here/is/another/one'
CDPATH+=':/Users/benjamin/and/a/third/line'