Re: Bash: testing a variable
On 7/9/2021 9:54 PM, Charles Curley wrote:
I'd like to check two things:
* Whether a given path is not already in the $PATH variable
* Whether the given path already exists
If both are true, I'd like to add the given path to the $PATH variable.
I can add the given path, and test for the existence of the given path.
I can write expressions that work to detect the given path in $PATH.
What I don't seem able to do is combine all that in a script.
Here's what I have for the script:
#!/bin/bash
# A short script for testing some code.
# pelican seems to like local installations here.
SUBSTR="${HOME}"/\.local/bin/
echo Substr is "${SUBSTR}"
# if [[ ! ${PATH} =~ .*/home/charles/.local/bin.* ]] ; then
[[ $PATH =~ \/home\/charles\/... ]] && echo match || echo nomatch
That is, escaping the backslash.
if [[ $( echo "$PATH" | grep -E -v "${SUBSTR}" ) ]] ; then
Try the -q opt to grep or redirecting the output to the null device:
'if $(echo $PATH | grep -v $SUBSTR 2>&1); then'
I call the script with the . operator: ". test.sh"
Personally, I would invoke the script as './try.sh' and use sourcing
('source, '.') to include libraries...
I would also not use 'test' as a name for a script (could be confused
with the test command).
Why do I always end up adding the given path, even if it is already in
$PATH?
Because if there is a match, grep will print the value of the match (in
this case the content of $PATH).
So the condition will always be 0.
--
John Doe
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