pass a variable into a ascii art - bash

Question

In bash/ Ubuntu,
If there is a ASCII art file: "ascii-art" in the following
|__ __| ____|/ ____|__ __|
| | | |__ | (___ | |
| | | __| \___ \ | |
| | | |____ ____) | | |
|_| |______|_____/ |_| Client ${CLIENT_ID}
Is there anyway to pass the variable "${CLIENT_ID}" into the ascii-art every time we call it?
The way we call it at the moment:
cat ascii-art
The following ways don't work
1. cat ascii-art | CLIENT_ID="1"
or
Add one more line in the first line of the file "ascii-art"
. command_line_parse.sh -c ${CLIENT_ID}
|__ __| ____|/ ____|__ __|
| | | |__ | (___ | |
| | | __| \___ \ | |
| | | |____ ____) | | |
|_| |______|_____/ |_| Client ${CLIENT_ID}
Then
cat ascii-art | CLIENT_ID="1"
Could any guru enlighten? Thanks.

Answer 1

The envsubst tool is written for exactly this purpose:
CLIENT_ID=foo envsubst ascii-art
This is a preferable tool to sed, which restricts the range of possible values (if you had a / in your id, or even worse a semicolon followed by another sed command, serious bugs could ensue).
See also TemplateFiles on the Wooledge wiki, which includes a native-bash implementation for systems without GNU gettext (which includes envsubst).

Answer 2

The following evaluates the echo command for the contents of the file:
CLIENT_ID=1000 eval "$(cat <<EOC
echo -e "$(<ascii-art)"
EOC
)"
CLIENT_ID=1000 assigns environment variable for the eval command
eval accepts a here document as its single argument
$(<ascii-art), in Bash, does the same as $(cat ascii-art)
EDIT regarding the scary eval
It's true that we should avoid using eval. But we should also understand the
purpose of the command and do use it when appropriate. We should understand
the security risks, and decide whether we should, or we shouldn't use eval
in certain situations.
The Bash Hackers Wiki gives a good description
of eval:
Perhaps the easiest way to think about eval is that it works in the same way
as running bash -c "bash code…" from a script, except in the case of
eval, the given code is executed in the current shell environment rather
than a child process.
So eval just executes the shell code we pass. How often we execute
external commands from Bash scripts? I guess, quite often. And the commands
are just trusted executables which may well be Bash scripts themselves.
Then why should one be scared of evaluating some echo "trusted content"?
It is up to the user(OP) to decide whether it is safe to use eval in certain
situation. However, this answer definitely gives him an option; it is an
alternate solution. So I don't understand the downvote on this answer.

Answer 3

First: look at the programs figlet, toilet or cowasy. These are probably finished implementation of what you want.
If you want to write it yourself:
sed 's/${CLIENT_ID}/42/g' ascii-art

Answer 4

Modified from RotatingPieces' answer above
First modify the "ascii-art" file, and change "${CLIENT_ID}" into "CLIENT_ID_ART"
|__ __| ____|/ ____|__ __|
| | | |__ | (___ | |
| | | __| \___ \ | |
| | | |____ ____) | | |
|_| |______|_____/ |_| Client CLIENT_ID_ART
Now the following approach might not be very elegant, but it works perfectly
CLIENT_ID="1" # The ${CLIENT_ID} will actually be from the command line parser
echo "sed 's/CLIENT_ID_ART/"${CLIENT_ID}"/g' ascii-art > call_art
chmod +x call_art
./call_art &
rm -f call_art
The above will print out the following in the output
|__ __| ____|/ ____|__ __|
| | | |__ | (___ | |
| | | __| \___ \ | |
| | | |____ ____) | | |
|_| |______|_____/ |_| Client 1