How to specify multiple input arguments stored in a file to a command?

Question

I would like to convert several webpages into a pdf file, by:

wkhtmltopdf http://think-like-a-git.net/sections/about-this-site.html http://think-like-a-git.net/sections/about-this-site/who-this-site-is-for.html all.pdf

If I put the two input arguments into a text file called "links":

http://think-like-a-git.net/sections/about-this-site.html 
http://think-like-a-git.net/sections/about-this-site/who-this-site-is-for.html

how shall I specify the input arguments in terms of the file? The following doesn't work:

$ wkhtmltopdf "$(cat links)" all.pdf
Loading pages (1/6)
Counting pages (2/6)
Resolving links (4/6)
Loading headers and footers (5/6)
Printing pages (6/6)
Done
Exit with code 1 due to network error: ContentNotFoundError

Answer 1

When you used double quotes in "$(cat links)", the shell treated the whole content of file as one string, not separated fields (with each field is one line in file).

You can do something like this:

set -f  # Turn off globbing
IFS='   # Split on newline only
'
wkhtmltopdf $(cat links) all.pdf

Answer 2

You could:

readarray -t a < file
wkhtmltopdf "${a[@]}" all.pdf

---

• readarray reads the file into an array line by line, -t removes the trailing newline.
• "${a[@]}" refers to all array elements. This generates a command in the form:

wkhtmltopdf "${a[0]}" "${a[1]}" "${a[2]}" "..." all.pdf