I'm trying to list script's argument by printf function. Arguments are counted by iteration of $i. What should be in printf function?
I need something like
eval echo \$$i
but in printf function.
Edit: Have while cycle with iteration of $i and among other code, I have
printf "%s" $i
But, instead of $i, I need some code, that shows me value of argument.
In my case, it is name of file, and I need list them. One file in one iteration.
As noted in a comment, you normally do that with a loop such as:
i=1
for arg in "$@"
do
echo "$i: [$arg]"
((i++))
done
(If echo isn't allowed, use printf "%s\n" … where the … is whatever would have followed echo.)
You might also use indirect expansion to avoid the use of eval:
for i in 1 2 3 4; do echo "$i: [${!i}]"; done
You can generalize that with:
for i in $(seq 1 $#); do echo "$i: [${!i}]"; done
or
for ((i = 1; i <= $#; i++)); do echo "$i: [${!i}]"; done
For example, given:
set -- a b 'c d' ' e f '
all the loops produce the output:
1: [a]
2: [b]
3: [c d]
4: [ e f ]
The square brackets are merely there to delimit the argument values; it allows you to see the trailing blanks on the fourth line of output.
You might also be able to use:
printf "[%s]\n" "$@"
to get:
[a]
[b]
[c d]
[ e f ]
It is not very clear what you are asking for, but this will list the arguments passed to the script:
while [ $# -gt 0 ]; do
printf "%s\n" "$1"
shift
done
printf "%s\n" "$@" and get the same result.
shift should do what you want.I guess what you are asking for is how to make the indirect reference to positional parameter i (i containing the position):
print "%s\n" ${!i}
"hello world" would render as two lines, one with hello and the other with world.To get your arguments in such a way that they can be fed back into the shell with the exact same value, the following bash extension can be used:
printf '%q ' "$@"; printf '\n'
This works even for rather unusual cases. Let's say that one of your arguments contains a newline:
./your-script 'hello
world' 'goodbye world'
This will be represented in the printf output:
$'hello\nworld' goodbye\ world
...with something you can use again in the shell:
$ echo $'hello\nworld' goodbye\ world
hello
world goodbye world
i=1;for arg in "$@"; do echo "$i: $arg"; ((i++)); done, iterating through the list of arguments. Is there any reason why you can't do that too?echo; use:i=1;for arg in "$@"; do printf "%s\n" "$i: $arg"; ((i++)); done. That produces the same thing as theechodoes. You can vary the formatting to suit yourself. See also my answer. It would also help if you showed enough context for what you want to do and what you have tried that we can see how to help you properly, rather than having to guess what it is you want us to help you with.printf '%q'. Be aware that this is a bashism, unavailable in POSIX printf.