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, 13 insertions, 11 deletions

diff --git a/src/fnet/main.c b/src/fnet/main.c
index fc36ae977..d1c8170ca 100644
--- a/src/fnet/main.c
+++ b/src/fnet/main.c
@@ -35,19 +35,21 @@ void fmessage(char* fmt, ...) { // TODO: this function is duplicated in src/fire
         fflush(0);
 }
 
+static const char *const usage_str =
+        "Usage:\n"
+        "\tfnet create veth dev1 dev2 bridge child\n"
+        "\tfnet create macvlan dev parent child\n"
+        "\tfnet moveif dev proc\n"
+        "\tfnet printif\n"
+        "\tfnet printif scan\n"
+        "\tfnet config interface dev ip mask mtu\n"
+        "\tfnet config mac addr\n"
+        "\tfnet config ipv6 dev ip\n"
+        "\tfnet ifup dev\n"
+        "\tfnet waitll dev\n";
 
 static void usage(void) {
-        printf("Usage:\n");
-        printf("\tfnet create veth dev1 dev2 bridge child\n");
-        printf("\tfnet create macvlan dev parent child\n");
-        printf("\tfnet moveif dev proc\n");
-        printf("\tfnet printif\n");
-        printf("\tfnet printif scan\n");
-        printf("\tfnet config interface dev ip mask mtu\n");
-        printf("\tfnet config mac addr\n");
-        printf("\tfnet config ipv6 dev ip\n");
-        printf("\tfnet ifup dev\n");
-        printf("\tfnet waitll dev\n");
+        puts(usage_str);
 }
 
 int main(int argc, char **argv) {