Move usage text into usage_str var

For consistency and readability.

Note: This also makes exactly one extra blank line be printed at the end
of every usage text, which is currently only done in the following
files:

* src/fcopy/main.c
* src/fnettrace-dns/main.c
* src/fnettrace-icmp/main.c
* src/fnettrace-sni/main.c
* src/fnettrace/main.c
* src/profstats/main.c

1 files changed, 6 insertions, 4 deletions

diff --git a/src/fnettrace-icmp/main.c b/src/fnettrace-icmp/main.c
index 714917547..516a9fc5b 100644
--- a/src/fnettrace-icmp/main.c
+++ b/src/fnettrace-icmp/main.c
@@ -201,11 +201,13 @@ static void run_trace(void) {
         close(s);
 }
 
+static const char *const usage_str =
+        "Usage: fnettrace-icmp [OPTIONS]\n"
+        "Options:\n"
+        "   --help, -? - this help screen\n";
+
 static void usage(void) {
-        printf("Usage: fnettrace-icmp [OPTIONS]\n");
-        printf("Options:\n");
-        printf("   --help, -? - this help screen\n");
-        printf("\n");
+        puts(usage_str);
 }
 
 int main(int argc, char **argv) {