Commenting in a Bash script


Question

How can I comment on each line of the following lines from a script?

   cat ${MYSQLDUMP} | \
   sed '1d' | \
   tr ",;" "\n" | \
   sed -e 's/[asbi]:[0-9]*[:]*//g' -e '/^[{}]/d' -e 's/""//g' -e '/^"{/d' | \
   sed -n -e '/^"/p' -e '/^print_value$/,/^option_id$/p' | \
   sed -e '/^option_id/d' -e '/^print_value/d' -e 's/^"\(.*\)"$/\1/' | \
   tr "\n" "," | \
   sed -e 's/,\([0-9]*-[0-9]*-[0-9]*\)/\n\1/g' -e 's/,$//' | \
   sed -e 's/^/"/g' -e 's/$/"/g' -e 's/,/","/g' >> ${CSV}

If I try and add a comment like:

cat ${MYSQLDUMP} | \ # Output MYSQLDUMP File

I get:

#: not found

Is it possible to comment here?

1
146
5/1/2019 6:16:35 AM

Accepted Answer

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 clean 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

See Stack Overflow question How to Put Line Comment for a Multi-line Command.

183
12/6/2017 2:57:04 PM

The trailing backslash must be the last character on the line for it to be interpreted as a continuation command. No comments or even whitespace are allowed after it.

You should be able to put comment lines in between your commands

# output MYSQLDUMP file
cat ${MYSQLDUMP} | \
# simplify the line
sed '/created_at/d' | \
# create some newlines
tr ",;" "\n" | \
# use some sed magic
sed -e 's/[asbi]:[0-9]*[:]*//g' -e '/^[{}]/d' -e 's/""//g' -e '/^"{/d' | \
# more magic
sed -n -e '/^"/p' -e '/^print_value$/,/^option_id$/p' | \
# even more magic
sed -e '/^option_id/d' -e '/^print_value/d' -e 's/^"\(.*\)"$/\1/' | \
tr "\n" "," | \
# I hate phone numbers in my output
sed -e 's/,\([0-9]*-[0-9]*-[0-9]*\)/\n\1/g' -e 's/,$//' | \ 
# one more sed call and then send it to the CSV file
sed -e 's/^/"/g' -e 's/$/"/g' -e 's/,/","/g' >> ${CSV}

Licensed under: CC-BY-SA with attribution
Not affiliated with: Stack Overflow
Icon