Prefix to each output of a command on runtime

I assume that what you are doing in your allcommands.sh is:

command1.sh
command2.sh

Just relace it with

command1.sh | sed "s/^/[command1] /"
command2.sh | sed "s/^/[command2] /"

A minimal example of allcommands.sh:

#!/bin/bash
for i in command{1,2}.sh; do
    ./"$i" | sed 's/^/['"${i%.sh}"'] /'
done

With command1.sh and command2.sh executable and in the same directory just echoing the wanted strings, this gives the shell output:

$ ./command1.sh 
file exists
file moved
$ ./command2.sh 
file copied
file emptied
$ ./allcommands.sh 
[command1] file exists
[command1] file moved
[command2] file copied
[command2] file emptied

Quick sed breakdown

sed 's/^/['"${i%.sh}"'] /'

• s/ enters "regexp pattern match and replace" mode
• ^/ means "match the beginning of every line"
• ${i%.sh} happens in the shell context and means "$i, but strip the suffix .sh"
• ['"${i%.sh}"'] / at first prints a [, then exits the quoted context to grab the $i variable from the shell, then re-enters to finish with the ] and a space.