#Linux技巧 fg命令（Re-enter interactive mode after Ctrl-z）

fg [jobspec]
Resume jobspec in the foreground, and make
it the current job. If jobspec is not
present, the shell’s notion of the current
job is used. The return value is that of
the command placed into the foreground, or
failure if run when job control is dis-
abled or, when run with job control
enabled, if jobspec does not specify a
valid job or jobspec specifies a job that
was started without job control.