I have a Bash script:
How would I loop through a list of numbered variables and then make the variable into a loop.
Example:
//Variables
DIR="/home/"
LIMIT=8
1="cupcake/"
2="cake/"
3="icecream/"
4="donut/"
5="cocoa/"
6="whipcream/"
7="cookie/"
8="coffee/"
for i in {1..8} // The number of variables
do
cd "$DIR${i}"; // cd /home/cupcake/
make something;
done
Two ways will be reasonable.
Using positional parameters:
set "cupcake" "cake" "icecream" "donut" "cocoa" "whipcream" "cookie" "coffee"
for i; do
cd "${DIR}/${i}" || continue
# do something
done
It’s not in custom to store final slash of path in variables, so I use "${DIR}/${i}". Anyway, cd won’t fail at /home//cupcake.
Or using array:
A=( "cupcake" "cake" "icecream" "donut" "cocoa" "whipcream" "cookie" "coffee" )
for i in "${A[@]}"; do
cd "${DIR}/${i}" || continue
# do something
done
Please note, you should use "${A[@]}" to handle spaces properly, not ${A[*]}. || continue interrupts current iteration if cd fails.
Array obviously is more flexible: you can explicitly set a position as you tried to do in your question
A=(
[1]="cupcake"
[7]="cookie"
[2]="cake"
[3]="icecream"
[4]="donut"
[6]="whipcream"
[5]="cocoa"
[8]="coffee"
)
edit any single element later
A[4]="doughnut"
delete any element
unset A[4]
and so on.
I'll pretend that your numbered variables are parameters. That's what numbered variables are for.
for i in {1..8} // The number of variables
do
eval cd "$DIR\${$i}"; // cd /home/cupcake/
make something;
done
However, if this is indeed parameters, you can safely use $1 and keep shifting until you've referenced them all.
for i in {1..8} // The number of variables
do
cd "$DIR$1"; // cd /home/cupcake/
make something;
shift
done
Instead of using for {1..8} you can check for the number of parameters passed $#.
while [ $# -gt 0 ] // The number of variables
do
cd "$DIR$1"; // cd /home/cupcake/
make something;
shift
done
eval to reference variable indirect: ${!i}. cd "${DIR}${!i}"You can't. Numbered variables are reserved for script/function arguments. Rename them.
set one two three four then check the values of $1 to $4.I suspect you want an array which also allows a for loop, although it would look more like
for subdir in ${dirarray[*]}
do
cd "$DIR$subdir";
make something;
done
for subdir in ${dirarray[*]} it fails to handle spaces. Use "${dirarray[@]}".
#, not with//.