Inline comments for Bash? - bash

Question

I'd like to be able to comment out a single flag in a one-line command. Bash only seems to have from # till end-of-line comments. I'm looking at tricks like:
ls -l $([ ] && -F is turned off) -a /etc
It's ugly, but better than nothing. Is there a better way?
The following seems to work, but I'm not sure whether it is portable:
ls -l `# -F is turned off` -a /etc

Answer 1

My preferred is:
Commenting in a Bash script
This will have some overhead, but technically it does answer your question
echo abc `#put your comment here` \
def `#another chance for a comment` \
xyz etc
And for pipelines specifically, there is a cleaner solution with no overhead
echo abc | # normal comment OK here
tr a-z A-Z | # another normal comment OK here
sort | # the pipelines are automatically continued
uniq # final comment
How to put a line comment for a multi-line command

Answer 2

I find it easiest (and most readable) to just copy the line and comment out the original version:
#Old version of ls:
#ls -l $([ ] && -F is turned off) -a /etc
ls -l -a /etc

Answer 3

$(: ...) is a little less ugly, but still not good.

Answer 4

Here's my solution for inline comments in between multiple piped commands.
Example uncommented code:
#!/bin/sh
cat input.txt \
| grep something \
| sort -r
Solution for a pipe comment (using a helper function):
#!/bin/sh
pipe_comment() {
cat -
}
cat input.txt \
| pipe_comment "filter down to lines that contain the word: something" \
| grep something \
| pipe_comment "reverse sort what is left" \
| sort -r
Or if you prefer, here's the same solution without the helper function, but it's a little messier:
#!/bin/sh
cat input.txt \
| cat - `: filter down to lines that contain the word: something` \
| grep something \
| cat - `: reverse sort what is left` \
| sort -r

Answer 5

Most commands allow args to come in any order. Just move the commented flags to the end of the line:
ls -l -a /etc # -F is turned off
Then to turn it back on, just uncomment and remove the text:
ls -l -a /etc -F

Answer 6

How about storing it in a variable?
#extraargs=-F
ls -l $extraargs -a /etc

Answer 7

If you know a variable is empty, you could use it as a comment. Of course if it is not empty it will mess up your command.
ls -l ${1# -F is turned off} -a /etc
§ 10.2. Parameter Substitution

Answer 8

For disabling a part of a command like a && b, I simply created an empty script x which is on path, so I can do things like:
mvn install && runProject
when I need to build, and
x mvn install && runProject
when not (using Ctrl + A and Ctrl + E to move to the beginning and end).
As noted in comments, another way to do that is Bash built-in : instead of x:
$ : Hello world, how are you? && echo "Fine."
Fine.

Answer 9

It seems that $(...) doesn't survive from ps -ef.
My scenario is that I want to have a dummy param that can be used to identify the very process. Mostly I use this method, but the method is not workable everywhere. For example, python program.py would be like
mkdir -p MyProgramTag;python MyProgramTag/../program.py
The MyProgramTag would be the tag for identifying the process started.