Recursive bash linux script

Question

is it possible to assign the value of a call to a recursive script, to a variable? Here is my code, the error says that on line 10: RIS = 2*1... 3*2 etc That seems good work, but RIS is not assigned to a real value.

DECR=$1

if [[ ${DECR} -gt 0 ]] ; then
    echo ${DECR}
    ((DECR2 = ${DECR}-1))
    ((RIS = ${DECR} * `./fattoriale1.sh ${DECR2}`))
else
    ((RIS=1))
fi

echo ${RIS}

Error: ./fattoriale1.sh: riga 9: ((: RIS = 2 * 1
1: errore di sintassi nell'espressione (il token dell'errore è "1")
./fattoriale1.sh: riga 9: ((: RIS = 3 * 2
2: errore di sintassi nell'espressione (il token dell'errore è "2")
./fattoriale1.sh: riga 9: ((: RIS = 4 * 3
6: errore di sintassi nell'espressione (il token dell'errore è "6")
12

Thanks.

@123, not so. This is perfectly legal: echo $(( `echo 42` - `false; echo $?` )) — glenn jackman
– glenn jackman, Commented Feb 4, 2016 at 11:23
@glennjackman That isn't (()) it's $(()). Actually looks like both can. My bad. — 123
– 123, Commented Feb 4, 2016 at 11:27

glenn jackman · Accepted Answer · 2016-02-04 11:21:28Z

1

You have 2 echo statements in your function, so if DECR > 0 then the output of the function contains a newline. The error message indicates you're trying to execute:

((RIS = 2 * 1
1))

Remove echo $DECR or change it to print to stderr: echo $DECR >&2

answered Feb 4, 2016 at 11:21

glenn jackman

249k42 gold badges233 silver badges362 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

glc78 Over a year ago

Thanks, it works. I really didn't know how to do, that echo was only a check output. Another question: is there a way to write the same scipt using only one DECR variable instead of two?

glenn jackman Over a year ago

yes: factorial () { local n=$1; [[ $n -eq 1 ]] && echo 1 || echo $(( n * $( factorial $((n-1)) ) )); }

Collectives™ on Stack Overflow

Recursive bash linux script

1 Answer 1

2 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

2 Comments

Your Answer

Sign up or log in

Post as a guest

Related