Unable to add element to array in bash

Question

I have the following problem. Let´s assume that $@ contains only valid files. Variable file contains the name of the current file (the file I\'m cu

Answer 1

Your problem is that the while loop runs in a subshell because it is the second command in a pipeline, so any changes made in that loop are not available after the loop exits.

You have a few options. I often use { and } for command grouping:

nm "$@" |
{
while read line
do
    …
done
for j in "${array[@]}"
do
    echo "$j"
done
}

In bash, you can also use process substitution:

while read line
do
    …
done < <(nm "$@")

---

Also, it is better to use $(…) in place of back-quotes `…` (and not just because it is hard work getting back quotes into markdown text!).

Your line:

element="`echo \"$line\" | sed -n \"s/^U \([0-9a-zA-Z_]*\).*/$file:\1/p\"`"

could be written:

element="$(echo "$line" | sed -n "s/^U \([0-9a-zA-Z_]*\).*/$file:\1/p")"

or even:

element=$(echo "$line" | sed -n "s/^U \([0-9a-zA-Z_]*\).*/$file:\1/p")

It really helps when you need them nested. For example, to list the lib directory adjacent to where gcc is found:

ls -l $(dirname $(dirname $(which gcc)))/lib

vs

ls -l `dirname \`dirname \\\`which gcc\\\`\``/lib

I know which I find easier!