Bash Getopts ：让你的脚本支持命令行参数

#!/bin/bash
 
######################################################################
#This is an example of using getopts in Bash. It also contains some
#other bits of code I find useful.
#Author: Linerd
#Website: http://tuxtweaks.com/
#Copyright 2014
#License: Creative Commons Attribution-ShareAlike 4.0
#http://creativecommons.org/licenses/by-sa/4.0/legalcode
######################################################################
 
#Set Script Name variable
SCRIPT=`basename ${BASH_SOURCE[0]}`
 
#Initialize variables to default values.
OPT_A=A
OPT_B=B
OPT_C=C
OPT_D=D
 
#Set fonts for Help.[译注: 这里tput用来更改终端文本属性,比如加粗，高亮等]
NORM=`tput sgr0`
BOLD=`tput bold`
REV=`tput smso`
 
#Help function
function HELP {
echo -e \\n"Help documentation for ${BOLD}${SCRIPT}.${NORM}"\\n
echo -e "${REV}Basic usage:${NORM} ${BOLD}$SCRIPT file.ext${NORM}"\\n
echo "Command line switches are optional. The following switches are recognized."
echo "${REV}-a${NORM}  --Sets the value for option ${BOLD}a${NORM}. Default is ${BOLD}A${NORM}."
echo "${REV}-b${NORM}  --Sets the value for option ${BOLD}b${NORM}. Default is ${BOLD}B${NORM}."
echo "${REV}-c${NORM}  --Sets the value for option ${BOLD}c${NORM}. Default is ${BOLD}C${NORM}."
echo "${REV}-d${NORM}  --Sets the value for option ${BOLD}d${NORM}. Default is ${BOLD}D${NORM}."
echo -e "${REV}-h${NORM}  --Displays this help message. No further functions are performed."\\n
echo -e "Example: ${BOLD}$SCRIPT -a foo -b man -c chu -d bar file.ext${NORM}"\\n
exit 1
}
 
#Check the number of arguments. If none are passed, print help and exit.
NUMARGS=$#
echo -e \\n"Number of arguments: $NUMARGS"
if [ $NUMARGS -eq 0 ]; then
HELP
fi
 
### Start getopts code ###
 
#Parse command line flags
#如果选项需要后跟参数，在选项后面加":"
#注意"-h"选项后面没有":"，因为他不需要参数。选项字符串最开始的":"是用来去掉来自getopts本身的报错的，同时获取不能识别的选项。（译注：如果选项字符串不以":"开头，发生错误（非法的选项或者缺少参数）时，getopts会向错误输出打印错误信息；如果以":"开头，则不会打印[在man中叫slient error reporting]，同时将出错的选项赋给OPTARG变量）
 
while getopts :a:b:c:d:h FLAG; do
case $FLAG in
a)  #set option "a"
OPT_A=$OPTARG
echo "-a used: $OPTARG"
echo "OPT_A = $OPT_A"
;;
b)  #set option "b"
OPT_B=$OPTARG
echo "-b used: $OPTARG"
echo "OPT_B = $OPT_B"
;;
c)  #set option "c"
OPT_C=$OPTARG
echo "-c used: $OPTARG"
echo "OPT_C = $OPT_C"
;;
d)  #set option "d"
OPT_D=$OPTARG
echo "-d used: $OPTARG"
echo "OPT_D = $OPT_D"
;;
h)  #show help
HELP
;;
\?) #unrecognized option - show help
echo -e \\n"Option -${BOLD}$OPTARG${NORM} not allowed."
HELP
#在这里如果你不想打印完整的帮助信息，只想显示简单的错误信息，去掉上面的两行，同时使用下面的两行。
#echo -e "Use ${BOLD}$SCRIPT -h${NORM} to see the help documentation."\\n
#exit 2
;;
esac
done
 
shift $((OPTIND-1))  #This tells getopts to move on to the next argument.
 
### End getopts code ###
 
 
### Main loop to process files ###
 
#这里你可以用你的脚本处理逻辑来替代。这个例子只是在终端中打印文件的文件名和后缀名。你可以把任意其他的文件处理任务放到这个while-do循环中。
 
while [ $# -ne 0 ]; do
FILE=$1
TEMPFILE=`basename $FILE`
#TEMPFILE="${FILE##*/}"  #另外一种获取不带后缀的文件名的方法。
FILE_BASE=`echo "${TEMPFILE%.*}"`  #file without extension
FILE_EXT="${TEMPFILE##*.}"  #file extension
 
 
echo -e \\n"Input file is: $FILE"
echo "File withouth extension is: $FILE_BASE"
echo -e "File extension is: $FILE_EXT"\\n
shift  #Move on to next input file.
done
 
### End main loop ###
 
exit 0
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.
25.
26.
27.
28.
29.
30.
31.
32.
33.
34.
35.
36.
37.
38.
39.
40.
41.
42.
43.
44.
45.
46.
47.
48.
49.
50.
51.
52.
53.
54.
55.
56.
57.
58.
59.
60.
61.
62.
63.
64.
65.
66.
67.
68.
69.
70.
71.
72.
73.
74.
75.
76.
77.
78.
79.
80.
81.
82.
83.
84.
85.
86.
87.
88.
89.
90.
91.
92.
93.
94.
95.
96.
97.
98.
99.
100.
101.
102.
103.
104.
105.
106.
107.
108.
109.
110.
111.
112.
113.
114.

chmod +x ~/bin/options
1.

options -h
1.

options -z
1.

options -d bar -c chu -b man -a foo example1.txt example2.txt
1.