Shell Programming and Scripting

A more efficient approach.

Code:

if grep -q '\.order$'; then
    echo match
else
    echo no match
fi

It's more efficient in several ways.

First, fewer subshells need to be forked.

Second, since grep's output isn't required, there's no need to pipe data from grep to a command substitution parent shell.

Third, suppose that there are very many matches in the ls output. We only need to find the first one. Once a single match is found, with -q, grep can exit immediately since the result is known to be true.

On an unrelated note, unless you intend to allow some sort of expansion between them, or unless you are trying to avoid a collision with another set of quotes, it's a good habit to use single quotes instead of double quotes. Also, while a trivial difference, it's also more efficient to parse single-quoted text.

Regards,
Alister

---------- Post updated at 03:43 PM ---------- Previous update was at 03:39 PM ----------

You can probably also redirect stdout to /dev/null and test the exit status directly.

Code:

if ls *.bin >/dev/null 2>&1; then

Regards,
Alister

---------- Post updated at 03:46 PM ---------- Previous update was at 03:43 PM ----------

With the usual shell defaults, the if-condition will always succeed, since if nothing matches the pattern the pattern remains unchanged and is assigned as the sole member of the array. For this code to work, nullglob must be enabled.

Regards,
Alister

---------- Post updated at 03:59 PM ---------- Previous update was at 03:46 PM ----------

In spirit, the following is akin to Scrutinizer's approach, but instead of using a function parameter to isolate the first of potentially many matches, it uses the for-loop's list assignment and an unconditional break.

Code:

for f in *.order; do
    break
done

if [ -e "$f" ]; then
  echo yes
fi

Regards,
Alister