Pass string variable as string literal in bash

Question

I am trying to pass a string-valued variable as a literal string in bash:

TEXT='Esto concuerda con la observación de Hord, que afirma que las espinacas contienen mucha vitamina K, lo que ayuda a reducir la presión arterial y el riesgo de sufrir enfermedades cardiovasculares.'

python normalize.py \
    --text $TEXT \
    --language es \
    --cache_dir ./es_norm_cache_dir/

The script normalize.py expects a string, so the above should expand to:

python normalize.py \
    --text 'Esto concuerda con la observación de Hord, que afirma que las espinacas contienen mucha vitamina K, lo que ayuda a reducir la presión arterial y el riesgo de sufrir enfermedades cardiovasculares.' \
    --language es \
    --cache_dir ./es_norm_cache_dir/

i.e. including the (non-escaping) single quotes. This second call runs as desired.

How can I use a variable but still make the above call equivalent to the second code block written above?

... and it must be double quotes really, not single. Single quotes would escape the variable expansion. — Jardel Lucca, Sep 12 '22 at 14:37

Jardel Lucca · Answer 1 · 2022-09-12T15:22:18.687

0

You can easily see the effect of putting double quotes around the parameter with printf.

Here "first_word" and "second_word" are seeing as two parameters:

$ printf "%s\n" first_word second_word
first_word
second_word

While here as a single parameter:

$ printf "%s\n" "first_word second_word"
first_word second_word

This distinction holds true even if there's a variable expansion inside:

$ VAR="first_word second_word"
$ printf "%s\n" "${VAR}"
first_word second_word

More of this here:

[...] the double quotes protect the value of each parameter (variable) from undergoing word splitting or globbing should it happen to contain whitespace or wildcard characters

edited Sep 12 '22 at 15:22

answered Sep 12 '22 at 14:47

Jardel Lucca

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Please don't link the ABS -- it's notorious as a source of bad-practice examples and outdated information. The [Wooledge BashGuide](https://mywiki.wooledge.org/BashGuide) was written when the #bash IRC channel was tired of trying to get people to unlearn bad habits they picked up from the ABS, but there are plenty of other good resources as well -- see the [bash tag wiki](https://stackoverflow.com/tags/bash/info) for a list. – Charles Duffy Sep 12 '22 at 14:54
Thanks @CharlesDuffy! I've just done a quick search and confirmed this fame from ABS of having outdated info.! Will be more careful next time I see it... – Jardel Lucca Sep 12 '22 at 15:25

Pass string variable as string literal in bash

1 Answers1