Created SC2126 (markdown)

SC2126.md

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+## Consider using grep -c instead of grep|wc.
+
+### Problematic code:
+
+    grep foo | wc -l
+
+### Correct code:
+
+    grep -c foo
+
+### Rationale:
+
+This is purely a stylistic issue. `grep` can count lines without piping to `wc`. 
+
+Note that in many cases, this number is only used to see whether there are matches (i.e. `> 0`). In these cases, it's better and more efficient to use `grep -q` and check its exit status:
+
+    if grep -q pattern file
+    then
+      echo "The file contains the pattern"
+    fi
+
+### Exceptions
+
+If you e.g. want to count characters instead of lines, and you actually care about the number and not just whether it's greater than 0.