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Backticks are evil

Terminal - Backticks are evil
echo "The date is: $(date +%D)"
2009-03-07 15:51:59
User: atoponce
Functions: echo
Backticks are evil

This is a simple example of using proper command nesting using $() over ``. There are a number of advantages of $() over backticks. First, they can be easily nested without escapes:

program1 $(program2 $(program3 $(program4)))


program1 `program2 \`program3 \`program4\`\``

Second, they're easier to read, then trying to decipher the difference between the backtick and the singlequote: `'. The only drawback $() suffers from is lack of total portability. If your script must be portable to the archaic Bourne shell, or old versions of the C-shell or Korn shell, then backticks are appropriate, otherwise, we should all get into the habit of $(). Your future script maintainers will thank you for producing cleaner code.


There are 5 alternatives - vote for the best!

Terminal - Alternatives

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What others think

I totally agree.

Comment by CodSpirit 350 weeks and 5 days ago

That's why rc shell uses `{}, $ is too confusing too

Comment by maht 350 weeks and 5 days ago


Comment by linuxrawkstar 350 weeks and 5 days ago

@maht, i agree:

echo "The date is: {date +%D}"

would be easier. i wish i could do this in bash.

Comment by nickleus 315 weeks and 2 days ago

Bad example; it doesn't need command substitution:

date +"The date is %c"

(Not to mention that %D is the worst possible date format.)

Comment by cfajohnson 313 weeks and 6 days ago

@cfajohnson cute, but the purpose of the command is to show how to appropriately nest commands, not how to use the date command.

Comment by atoponce 283 weeks and 6 days ago

Yeah, evil but totally necessary.

For example, this won't work with $() but works just fine with back ticks:

x=1; case $x in 1) echo one ;; esac

Why? Because the 1) in the case confuses the $() parser.

Comment by zapatar 146 weeks and 4 days ago

Your point of view

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