据我所知，方括号通常用于将表达式括在 if else 语句中。
但我发现方括号没有“if”，如下所示：
[ -r /etc/profile.d/java.sh ] && . /etc/profile.d/java.sh
在下面的脚本中。
#!/bin/bash### BEGIN INIT INFO
# Provides: jbossas7
# Required-Start: $local_fs $remote_fs $network $syslog
# Required-Stop: $local_fs $remote_fs $network $syslog
# Default-Start: 2 3 4 5
# Default-Stop: 0 1 6
# Short-Description: Start/Stop JBoss AS 7
### END INIT INFO
# chkconfig: 35 92 1
## Include some script files in order to set and export environmental variables
## as well as add the appropriate executables to …