Say I let a user input as many arguments as he wants, how do read all the inputs?
So if a user typed in asdf asfd asdf, it should say 3 arguments Right now I have
#!/bin/bash
read $@
echo "There are $# arguments"
but whenever I type in anything it always equals 0
If you want to read all the parameters from a variable using the same style as if you would have done it from the command line. You could do it in a function
#!/bin/bash
function param_count() {
for arg in $@
do
echo " arg: $arg"
done
echo "arg count= $#"
}
read foo
param_count $foo
If you really want to read a line as a sequence of words, your best bet in bash is to read it into an array:
$ read -a words
And now a few words from our sponsor
$ echo ${#words[@]}
8
$ echo "${words[3]}"
few
But that's not the way to pass arguments to a shell script. read just splits lines into words using whitespace (or whatever IFS is set to.) It does not:
Passing arguments on the command line lets you do all of the above, making the utility more convenient to use, and does not require any extra work to extract the arguments, making the utility easier to write.
This is the way to get it:
read ARGUMENTS
set -- $ARGUMENTS
echo "There are $# arguments"
read ARGUMENTS
Read the input and save it into ARGUMENTS
set -- $ARGUMENTS
Set the positional parameters to the given input
At this point, you can use that input as if it was given in the command-line.
e.g.:
echo "$1"
echo "$2"
...
Delete read $@ line. Then launch your script with arguments. Just like this:
/path/to/script arg1 arg2 arg3 4 5 6
The output should be:
There are 6 arguments
for i; do echo $i; done Each argument can be accessed via: $1, $2, $3 ... $nHere is an example script that shows you how to get the argument count, access the individual arguments and read in a new variable:
#!/usr/bin/env bash
echo "There are $# arguments, they are:"
for arg in $@
do
echo " - $arg"
done
# Access the aguments
echo "The first argument is $1"
echo "The second argument is $2"
echo "The third argument is $3"
echo "All arguments: $@"
# Read a variable
read var
echo "Some var: $var"
