I’m trying to join all of the arguments to a Bash function into one single string with spaces separating each argument. I also need to have the string include single quotes around the whole string.
Here is what I have so far…
$array=("<a href="https://getridbug.com/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="e7c3a7">[email protected]</a>")
str="'"
for arg in "${array[@]}"; do
let $str=$str+$arg+" "
done
let $str=$str+"'"
Obviously this does not work but I’m wondering if there is a way to achieve this?
Answers:
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Method 1
I believe that this does what you want. It will put all the arguments in one string, separated by spaces, with single quotes around all:
str="'$*'"
$* produces all the scripts arguments separated by the first character of $IFS which, by default, is a space.
Inside a double quoted string, there is no need to escape single-quotes.
Example
Let us put the above in a script file:
$ cat script.sh #!/bin/sh str="'$*'" echo "$str"
Now, run the script with sample arguments:
$ sh script.sh one two three four 5 'one two three four 5'
This script is POSIX. It will work with bash but it does not require bash.
A variation: concatenating with slashes instead of spaces
We can change from spaces to another character by adjusting IFS:
$ cat script.sh #!/bin/sh old="$IFS" IFS='/' str="'$*'" echo "$str" IFS=$old
For example:
$ sh script.sh one two three four 'one/two/three/four'
Method 2
It’s easier than you think:
#!/bin/bash
array="${@}"
echo $array
chmod +x that, and run it:
$ ./example.sh --foo bar -b az --foo bar -b az
Method 3
update
Tl;dr, use
"'${array[*]}'"
To be clear, I don’t intend to replicate this answer. I just found there are minor differences to use @ and * to dereference all values from an array.
Under the hood, $* and [email protected] are all arrays, referring to the argv list.
From the question,
I’m trying to join all of the arguments to a Bash function into one single string with spaces separating each argument.
It has 2 sub-questions:
- concatenate the array input arguments into a string.
- pass the concatenated string as a single argument for the shell function.
First, concat array into a string,
array=("[email protected]")
str="'${array[@]}'"
# or
str="'${array[*]}'"
# or
str='"${array[*]}"'
Second, when you pass str to a function, let’s count the number of arguments that function received,
#!/usr/bin/env bash
arr=(a b c d)
function count_args() {
echo '$#' $#
}
count_args "'${arr[@]}'"
count_args '"${arr[@]}"'
count_args "'${arr[*]}'"
count_args '"${arr[*]}"'
output is
$# 4
$# 4
$# 1
$# 1
only arr[*] wraps the array into 1 argument for the shell function, why?
Cite from How to use arrays in bash script, which I found it’s useful for me,
echo ${array[*]}
echo ${array[@]}
Both syntax let us access all the values of the array and produce the same results, unless the expansion it’s quoted. In this case a difference arises: in the first case, when using @, the expansion will result in a word for each element of the array.
Whereas using * will group the entire array into one single argument during expansion.
All methods was sourced from stackoverflow.com or stackexchange.com, is licensed under cc by-sa 2.5, cc by-sa 3.0 and cc by-sa 4.0