1 #!/bin/bash
2
3 # Weird case from bash-help mailing list.
4 #
5 # "Evaluations of backticks in if statements". It doesn't relate to if
6 # statements but to $?, since && and || behave the same way.
7
8 # POSIX has a special rule for this. In OSH strict_argv is preferred so it
9 # becomes a moot point. I think this is an artifact of the
10 # "stateful"/imperative nature of $? -- it can be "left over" from a prior
11 # command, and sometimes the prior argv is []. OSH has a more "functional"
12 # implementation so it doesn't have this weirdness.
13
14 #### If empty command
15 if ''; then echo TRUE; else echo FALSE; fi
16 ## stdout: FALSE
17 ## status: 0
18
19 #### If subshell true
20 if `true`; then echo TRUE; else echo FALSE; fi
21 ## stdout: TRUE
22 ## status: 0
23
24 #### If subshell true WITH OUTPUT is different
25 if `sh -c 'echo X; true'`; then echo TRUE; else echo FALSE; fi
26 ## stdout: FALSE
27 ## status: 0
28
29 #### If subshell true WITH ARGUMENT
30 if `true` X; then echo TRUE; else echo FALSE; fi
31 ## stdout: FALSE
32 ## status: 0
33
34 #### If subshell false -- exit code is propagated in a weird way (strict_argv prevents)
35 if `false`; then echo TRUE; else echo FALSE; fi
36 ## stdout: FALSE
37 ## status: 0