Prepare arguments containing quoted string in variable

Question

In a Bash script, I call a program like this in several places:

numfmt --suffix=" B" --grouping 231210893

Where the number is different every time, but the other parameters stay the same.

I would now like to move the other parameters out of the many different calls, so they are centrally defined and can be easily changed. My attempt was like this:

NUMFMT='--suffix=" B" --grouping'
...
numfmt $NUMFMT 231210893

Unfortunately, this doesn't work. The quote signs are removed at some point, and numfmt complains about an uninterpretable extra argument B. I tried plenty of other versions, using other quotes both in the definition and in the use of NUMFMT, to no avail.

How do I do this properly? And if it's not too complicated, I would also like to understand why my version doesn't work and (hopefully) another one does.

See Why does my shell script choke on whitespace or other special characters? - in particular, the section How do I store a command in a variable? in @Gilles answer — steeldriver, Nov 18 '18 at 00:57

score 6 · Accepted Answer · edited Nov 18 '18 at 03:26

6

Try arrays:

NUMFMT=( --suffix=" B"   '--grouping' )
....
numfmt "${NUMFMT[@]}" 231210893

edited Nov 18 '18 at 03:26

filbranden

21,751
4
63
86

answered Nov 18 '18 at 01:21

I had to remove the "s in the first argument, but now it works perfectly. Thanks! – A. Donda Nov 18 '18 at 01:38

score 1 · Answer 2 · answered Nov 18 '18 at 11:52

1

Wouldn't that be an excellent case for an alias?

$ alias nfmtB='numfmt --suffix=" B" --grouping'
$ nfmtB 324235345656
324.235.345.656 B

answered Nov 18 '18 at 11:52

RudiC

8,969

Good idea but with a little catch: command aliases are disabled in scripts by default unless enabled with shopt -s expand_aliases. – David Foerster Nov 18 '18 at 12:29

Prepare arguments containing quoted string in variable

2 Answers2