Bash – Is it common to split larger script into multiple scripts and source them in the main script

bash

At the moment I'm developing a larger Bash script (it's an Open Source project of mine) and it's starting to become a mess. I've split up logic into functions, use local variables where I can and have only declared a handful global variables. Still, it is becoming pretty hard to maintain.

I thought about splitting the script up into multiple scripts and source them in my main script (similar to imports in other languages).

But I wonder if this is a feasible approach. First, sourcing multiple scripts could severly slow the execution time of the script, and second, it makes distribution harder.

So, is this a good approach, and do other (Open Source) projects do it the same way?

Best Answer

Yes, it is a common practice. For example, in the early days of Unix the shell code responsible for guiding the system through its boot phases to multiuser operation was a single file, /etc/rc. Today the boot process is controlled by many shell scripts, broken up by function, with common functions and variables sourced as needed from central locations. Linux distributions, Macs, BSDs, all have adopted this approach to varying degree.

Related Solutions

Bash – Run Multiple Scripts in Parallel Instead of Sequence

for((i=1;i<100;i++)); do nohup bash script${i}.sh & done

Bash Script – Source Encrypted GPG File On-the-Fly

You can do this using process substitution.

. <(gpg -qd "$encrypted_filename")

Here's an example:

% cat > to-source <<< 'echo "Hello"'
% . ./to-source                     
Hello
% gpg -e -r chris@chrisdown.name to-source
% . <(gpg -qd to-source.gpg)
Hello

gpg -d does not persist the file to disk, it just outputs it to stdout. <() uses a FIFO, which also does not result in the actual file data being written to disk.

In bash, . and source are synonyms, but . is more portable (it's part of POSIX), so I've used it here. Note, however, that <() is not as portable -- as far as I know it's only supported in bash, zsh, ksh88, and ksh93. pdksh and mksh have coprocesses which can have the same effect.

Best Answer

Related Solutions

Bash – Run Multiple Scripts in Parallel Instead of Sequence

Bash Script – Source Encrypted GPG File On-the-Fly

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