话虽如此，这是“解决方案”：PROMPT_COMMAND='LAST="`cat /tmp/x`"; exec >/dev/tty; exec > ...
子串削除: {varilable#*pattern}: 查找variable中自左而右第一次被pattern匹配到的串,将此串及向左的所有内容都删除{varilable##*pattern}: 查找variable中自左而右最后一次被pattern匹配到的串,将此串及向左的所有内容都删除 {varilable%pattern*}:查找variable中自右而左第一次被pattern匹配到的串,将此串及...
$!" # 返回最近一个后台命令的进程 ID sleep 1 echo "the last parameter of the previous command: \$_ $_" # 上一个命令的最后一个参数, 比如这里是1 选项参数传递 getopts 是一个用于解析命令行选项和参数的内置命令, 语法为 getopts optstring name optstring 是一个字符串, 定义脚本可以接收的选项, ...
Number of command-line arguments. 传递给脚本或函数的参数个数。 $_ The underscore variable is set at shell startup and contains the absolute file name of the shell or script being executed as passed in the argument list. Subsequently, it expands to the last argument to the previous command, ...
of the last child in the pipeline is the significant one. If the command or job was terminated by a signal, note that value also. */ termination_state = (job != NO_JOB) ?job_exit_status(job)一般通过这个流程来确定返回值。 :process_exit_status(child->status); ...
if command then command(s) elif command then commands(s) elif command then command(s) else command(s) fi 空命令 : 分支跳转 case variable in value1) command(s) ;; value2) command(s) ;; *) command(s) ;; esac 循环for variable in word_list ...
#Here we are reading the standard input and assigning it to the variable name with the read command. read name #We are now going back to standard output, by using echo and printing your name to the command line. echo "With standard input you have told me your name is: $name" ...
选项与参数:number:执行第几笔指令的意思;command:由最近的指令向前搜寻『指令串开头为 command』的那个指令,并执行;!!:就是执行上一个指令(相当于按↑按键后,按 Enter)[dmtsai@study~]$ history66man rm67alias68man history69history[dmtsai@study~]$!66<==执行第66笔指令[dmtsai@study~]$!!<==执行上一...
#Here we are reading the standard input and assigning it to the variable name with the read command. read name #We are now going back to standard output, by using echo and printing your name to the command line. echo "With standard input you have told me your name is: $name" ...
command(s) ;; ……… *) command(s) ;; esac 4、循环语句 4.1、for循环 格式: for variable in word_list do command(s) done 写成一行: for var in item1 item2 ... itemN; do command1; command2… done; C风格的形式: for (( EXP1; EXP2; EXP3 )) do command...