Unused variable SH-2034
Anti-pattern
Major
2 years ago
—
2 years old
uname appears unused. Verify use (or export if used externally)
34 export PATH=/usr/gnu/bin:$PATH
35fi
36
37uname=$(uname) 38
39includes_AIX='
40#include <net/if.h>includes_AIX appears unused. Verify use (or export if used externally)
36
37uname=$(uname)
38
39includes_AIX=' 40#include <net/if.h>
41#include <net/netopt.h>
42#include <netinet/ip_mroute.h>includes_Darwin appears unused. Verify use (or export if used externally)
52#define AF_LOCAL AF_UNIX
53'
54
55includes_Darwin=' 56#define _DARWIN_C_SOURCE
57#define KERNEL 1
58#define _DARWIN_USE_64_BIT_INODEincludes_DragonFly appears unused. Verify use (or export if used externally)
88#define TIOCREMOTE 0x80047469
89'
90
91includes_DragonFly=' 92#include <sys/types.h>
93#include <sys/event.h>
94#include <sys/select.h>includes_FreeBSD appears unused. Verify use (or export if used externally)
111#include <net/ip_mroute/ip_mroute.h>
112'
113
114includes_FreeBSD='115#include <sys/capsicum.h>
116#include <sys/param.h>
117#include <sys/types.h>
Description
Variables that are declared but not used for anything should be removed.
Problematic code:
foo=42
echo "$FOO"
Preferred code:
foo=42
echo "$foo"
Exceptions:
This warning may be falsely emitted when a variable is referenced indirectly, or it is intentionally not used.
- Indirection: It's the checker's intended behavior to emit this warning for any variable that is only referenced though indirection:
# foo generates a warning, even though it has five indirect references
foo=42
name=foo
echo "${!name} $((name))"
export "$name"; eval "echo $name"
declare -n name; echo "$name"
This is an intentional design decision and not a bug. If you have variables that will not have direct references, consider using an associative array in bash, or ignore this warning.
- Intentionally unused variables:
For throwaway variables, consider using
_as a dummy:
read _ last _ zip _ _ <<< "$str"
echo "$last, $zip"