Prefix to each output of a command on runtime

Question

I am trying to make a modular script. I have several scripts/commands which are called from a single script.
I want to prefix the output of each separate command.

Examle:

My files are allcommands.sh / command1.sh / command2.sh

command1.sh outputs
file exists
file moved

command2.sh outputs
file copied
file emptied

allcommands.sh runs the scripts command1.sh and command2.sh

I want to prefix each output of these two scripts like this:
[command1] file exists
[command1] file moved
[command2] file copied
[command2] file emptied

Solution 1

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] /"

Solution 2

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.

Comments

[j_kubik]

Try running each command piping it through sed "s/\^/command1 /"

[Ivan Dokov]

Give me please an example with the information that I give. I don't really understand the sed functionality. I'm sorry.

[Ivan Dokov]

Thanks for the clarifications. Your answer was helpful indeed, but @j_kubik's example was just the one I need.