I am doing some bash script and now I got one variable call source and one array called samples, like this:
source='country'
samples=(US Canada Mexico...)
as I want to expand the number of sources (and each source has its own samples) I tried to add some arguments to do this. I tried this:
source=""
samples=("")
if [ $1="country" ]; then
source="country"
samples="US Canada Mexico..."
else
echo "try again"
fi
but when I ran my script source countries.sh country it didn't work.
What am I doing wrong?
3 Answers
Don't forget about spaces:
source=""
samples=("")
if [ $1 = "country" ]; then
source="country"
samples="US Canada Mexico..."
else
echo "try again"
fi
You can use either "=" or "==" operators for string comparison in bash. The important factor is the spacing within the brackets. The proper method is for brackets to contain spacing within, and operators to contain spacing around. In some instances different combinations work; however, the following is intended to be a universal example.
if [ "$1" == "something" ]; then ## GOOD
if [ "$1" = "something" ]; then ## GOOD
if [ "$1"="something" ]; then ## BAD (operator spacing)
if ["$1" == "something"]; then ## BAD (bracket spacing)
Also, note double brackets are handled slightly differently compared to single brackets ...
if [[ $a == z* ]]; then # True if $a starts with a "z" (pattern matching).
if [[ $a == "z*" ]]; then # True if $a is equal to z* (literal matching).
if [ $a == z* ]; then # File globbing and word splitting take place.
if [ "$a" == "z*" ]; then # True if $a is equal to z* (literal matching).
I hope that helps!
It seems that you are looking to parse commandline arguments into your bash script. I have searched for this recently myself. I came across the following which I think will assist you in parsing the arguments:
I added the snippet below as a tl;dr
#using : after a switch variable means it requires some input (ie, t: requires something after t to validate while h requires nothing.
while getopts “ht:r:p:v” OPTION
do
case $OPTION in
h)
usage
exit 1
;;
t)
TEST=$OPTARG
;;
r)
SERVER=$OPTARG
;;
p)
PASSWD=$OPTARG
;;
v)
VERBOSE=1
;;
?)
usage
exit
;;
esac
done
if [[ -z $TEST ]] || [[ -z $SERVER ]] || [[ -z $PASSWD ]]
then
usage
exit 1
fi
./script.sh -t test -r server -p password -v
