Bash Variables In For Loop Range
Answer :
Yes, that's because brace-expansion occurs before parameter expansion. Either use another shell like zsh
or ksh93
or use an alternative syntax:
Standard (POSIX) sh syntax
i=1 while [ "$i" -le "$number" ]; do echo "$i" i=$(($i + 1)) done
Ksh-style for ((...))
for ((i=1;i<=number;i++)); do echo "$i" done
use eval
(not recommended)
eval ' for i in {1..'"$number"'}; do echo "$i" done '
use the GNU seq
command on systems where it's available
unset -v IFS # restore IFS to default for i in $(seq "$number"); do echo "$i" done
(that one being less efficient as it forks and runs a new command and the shell has to reads its output from a pipe).
Avoid loops in shells.
Using loops in a shell script are often an indication that you're not doing it right.
Most probably, your code can be written some other way.
You don't even need a for loop for this, just use the seq
command:
$ seq 100
Example
Here's the first 10 numbers being printed out:
$ seq 100 | head -10 1 2 3 4 5 6 7 8 9 10
You can use the following:
for (( num=1; num <= 100; num++ )) do echo $num done
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