Bash – assign array into variable as string

arraybashshellvariable

I have this code, it prints the correct result, but I can't figure out how to get the echo from the last line into a variable.

# hostname is 'tech-news-blog-324344' . Setting it into array host_name_array
IFS='-' read -r -a host_name_array <<< "$(hostname)" 
#removing the last part of string after last "-"
unset 'host_name_array[${#host_name_array[@]}-1]'
( IFS=$'-'; echo "${host_name_array[*]}" )  
#result is 'tech-news-blog'

How could get the value of the last line into a variable?
I've tried the following:

( IFS=$'-'; URL="${host_name_array[*]}" )

But I get the result "tech news blog" with spaces between pieces of array instead of '-'.

Best Answer

When IFS='-' read -r -a host_name_array <<< "$(hostname)" is ran, the array is (tech news blog 324344).

After the final element is removed with unset 'host_name_array[${#host_name_array[@]}-1]', the array is (tech news blog).

So, to get this to echo tech-news-blog, some substitution will have to be done, since echo "${host_name_array[*]}" will yield tech news blog:

With tr: echo "${host_name_array[*]}" | tr ' ' '-'

sed: echo "${host_name_array[*]}" | sed 's/ /-/g'

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Bash: split multi line input into array

Your attempt is close to the actual solution. The relevant flag can be found in the read help:

$ help read
...
      -d delim  continue until the first character of DELIM is read, rather
            than newline

It doesn't explicitly mention it, but you can set the delimiter to empty, and thus it'll read until EOF.

$ IFS=, read -d '' -a myarray < myfile

$ echo ${myarray[2]}
U2FsdGVkX1/c8rTTO41zVT7gB+KL+n7KoNCgM3vfchOyuvBngdXDGjXTvXTK0jz6

Bash – Issue with array length in bash script

You're flattening the input into a single value.

You should do

list=("${@}")

to maintain the array and the potential of whitespace in arguments.

If you miss out the " then something like ./script.sh "a b" 2 3 4 will return a length of 5 because the first argument will be split up. With " we get

$ cat x
#!/bin/bash
list=("${@}")

echo array = ${list[*]} and length = ${#list[*]}

$ ./x "a b" 2 3 4  
array = a b 2 3 4 and length = 4

Best Answer

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Bash: split multi line input into array

Bash – Issue with array length in bash script

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