getopts是bash shell的内建命令，作用是在shell脚本中解析命令行传递、传递给函数或传递给另一个调用的shell脚本的位置参数（选项或参数，后面会讲解，getopts只支持短选项，若要解析长选项请参考getopt）。
getopts命令语法:
getopts optstring name [arg]
相关的术语：
选项（option）：GNU风格的命令选项，如：-x,-y等减号加上单个字母的为短选项；--help为长选项；
选项的参数：某些选项之后必须尾随参数，如：-f xxx.conf，xxx.conf称为选项的参数;
参数：位于最后一个选项，空格之后的字符串;
optionstring：用于匹配option的字符串，optionstring中每个字母对应的是去除减号后的option（这里指短选项）;
[arg]：用来替代位置参数被getopts解析的，类似于将$@赋值给arg;
OPTIND: getopts的一个内置变量，表示下一个要处理的参数索引，每次shell或shell脚本执行的时候初始化为1;
name: getopts每解析到一个选项，都会将该选项对应的字符复制给name变量
getopts命令的简单解释：
1.optstring中如果字母后面跟随着冒号，表示该字母所表示的option后面是带参数的，参数值将被赋到OPTARG变量中。如test.sh中包含：getopts "i:" name; 那么在命令行执行test.sh -i 1.1.1.1时，$name=‘i‘,$OPTARG=1.1.1.1
getopts包含两种错误处理的模式
安静模式下：
2.optstring的第一个字符为冒号时，getopts将使用安静模式来报告错误（但不会有错误提示输出），生产环境中一般使用该模式；
3.如果输入一个无效的字符作为选项时（optstring中没包含的字符），将‘？’赋值给name变量，该无效选项的字符赋值给OPTARG变量；
4.如果选项要求跟随的参数没找到，getopts会将冒号":"赋值给name变量,设置OPTARG为发现的选项字符；
非安静模式下：
5.如果getopts不处于安静模式，一个无效的选项被发现，‘?‘将被设置到name变量中且unset OPTARG
6.如果选项要求的参数没找到，‘?‘将被设置到name，OPTARG将被unset，错误提示信息将被打印
退出状态：
7.如果shell中$OPTERR环境变量值为0，getopts将关闭错误信息的打印，即使optstring中第一个字符不是冒号。默认的$OPTERR值为1
8.getopts一般情况下解析位置参数（$0-$9），但位置参数超过这个范围时仍然能被正确解析
9.如果选项被发现（匹配optionstring）返回true，如果遇到了选项的结尾或者有错误则返回false
脚本实例：
1. 不带可选参数[arg]
#!/bin/bash
echo "OPTIND starts at $OPTIND"
while getopts ":q:p" optname
do
case "$optname" in
"p")
echo "Option $optname is specified"
;;
"q")
echo "Option $optname has value $OPTARG"
#shift 1
shift $((OPTIND-2))
;;
"?")
echo "Unknown option $OPTARG"
;;
":")
echo "No argument value for option $OPTARG"
;;
*)
# Should not occur
echo "Unknown error while processing options"
;;
esac
echo "OPTIND is now $OPTIND"
done
执行：
[root@dns1 ~]# bash test_getopts.sh -q aa -p -h
OPTIND starts at 1
Option q has value aa
OPTIND is now 3
Unknown option h
OPTIND is now 4
2. 带可选参数[arg]
#!/bin/bash
echo "OPTIND starts at $OPTIND"
while getopts ":q:p" optname "-q qarg" "-p" "-h"
do
case "$optname" in
"p")
echo "Option $optname is specified"
;;
"q")
echo "Option $optname has value $OPTARG"
;;
"?")
echo "Unknown option $OPTARG"
;;
":")
echo "No argument value for option $OPTARG"
;;
*)
# Should not occur
echo "Unknown error while processing options"
;;
esac
echo "OPTIND is now $OPTIND"
done
执行：
[root@dns1 ~]# bash test_getopts.sh
OPTIND starts at 1
Option q has value qarg
OPTIND is now 2
Option p is specified
OPTIND is now 3
Unknown option h
OPTIND is now 4
3. 实现一个添加yum源的脚本
#!/bin/bash
#
# Descrition: this script will download the yum repo file from mirrors.163.com and epel for CENTOS/REDHAT DISTIBUTE
# Author: Gateray Jo
# mail: hikaru211@126.com
set -e
prog=`basename $0`
arch=`uname -m`
release=`lsb_release -r | sed ‘s/.*:[[:space:]]*//‘`
function usage() {
cat<<eof
Usage: ./${prog} [options] [arg]
-h: print the command help.
-u: specified the baseurl for yum repository, must use with -ufn combination.
-f: specified the name of local repofile(no ".repo" ext name) which place in /etc/yum.repos.d/, must use with -ufn
combination.
-n: specified the repo‘s name in xxx.repo file, must use with -ufn combination.
-d: specified the url of repofile which will be download to /etc/yum.repos.d/.
By default, nothing options are specified which will download epel and 163 yum repofile.
eof
}
function default() {
major_rel=${release%%.*}
# download 163 repofile
printf "Download 163 repofile from mirrors.163.com:\n"
wget -P /etc/yum.repos.d http://mirrors.163.com/.help/CentOS${major_rel}-Base-163.repo
printf "Download epel repofile from http://dl.fedoraproject.org.:\n"
if [[ $arch = "x86_64" ]]; then
[ ${major_rel} -eq 5 ] && rpm -ivh http://dl.fedoraproject.org/pub/epel/5/x86_64/epel-release-5-4.noarch.rpm
[ ${major_rel} -eq 6 ] && rpm -ivh http://dl.fedoraproject.org/pub/epel/6/x86_64/epel-release-6-8.noarch.rpm
else
[ ${major_rel} -eq 5 ] && rpm -ivh http://dl.fedoraproject.org/pub/epel/5/i386/epel-release-5-4.noarch.rpm
[ ${major_rel} -eq 6 ] && rpm -ivh http://dl.fedoraproject.org/pub/epel/6/i386/epel-release-6-8.noarch.rpm
fi
return $?
}
[ $# -eq 0 ] && default && exit $?
while getopts ":hu:f:n:d:" optname; do
case $optname in
"h")
usage && exit 0
;;
"u")
u_opt=1
u_arg=$OPTARG
;;
"f")
f_opt=1
u_arg=$OPTARG
;;
"n")
n_opt=1
n_arg=$OPTARG
;;
"d")
wget -P /etc/yum.repos.d $OPTARG
exit $?
;;
"?")
echo "Unknown option $OPTARG"
usage && exit 1
;;
":")
echo "It is need a option value for $OPTARG"
usage && exit 1
;;
*)
echo ‘Unknown error!‘ && exit 1
;;
esac
done
if [ $u_opt -eq 1 -a $f_opt -eq 1 -a $n_opt -eq 1 ]; then
if [[ ${n_arg} =~ ‘-‘ ]]; then
echo "Invalid value for -n option, \"${n_arg}\" is include ‘-‘ character."
exit 1
fi
cat >> /etc/yum.repos.d/${f_arg}.repo <<eof
[${n_arg}]
name=${n_arg}
baseurl=${u_arg}
enabled=1
gpgcheck=0
eof
else
usage && exit 1
fi
脚本的执行：
1）打印命令帮助
[root@dns1 ~]# ./load_yum_repo.sh -h
Usage: ./load_yum_repo.sh [options] [arg]
-h: print the command help.
-u: specified the baseurl for yum repository, must use with -ufn combination.
-f: specified the name of local repofile(no ".repo" ext name) which place in /etc/yum.repos.d/, must use with -ufn
combination.
-n: specified the repo‘s name in xxx.repo file, must use with -ufn combination.
-d: specified the url of repofile which will be download to /etc/yum.repos.d/.
By default, nothing options are specified which will download epel and 163 yum repofile.
2）不带任何选项参数时，自动下载163和epel的yum源repofile
[root@dns1 ~]# ./load_yum_repo.sh
Download 163 repofile from mirrors.163.com:
--2015-04-04 22:23:05-- http://mirrors.163.com/.help/CentOS6-Base-163.repo
Resolving mirrors.163.com... 123.58.173.106
Connecting to mirrors.163.com|123.58.173.106|:80... connected.
HTTP request sent, awaiting response... 200 OK
Length: 2006 (2.0K) [application/octet-stream]
Saving to: “/etc/yum.repos.d/CentOS6-Base-163.repo”
100%[==========================================================================================>] 2,006 --.-K/s in 0.05s
2015-04-04 22:23:05 (39.2 KB/s) - “/etc/yum.repos.d/CentOS6-Base-163.repo” saved [2006/2006]
Download epel repofile from http://dl.fedoraproject.org.:
Retrieving http://dl.fedoraproject.org/pub/epel/6/x86_64/epel-release-6-8.noarch.rpm
warning: /var/tmp/rpm-tmp.wVrCDS: Header V3 RSA/SHA256 Signature, key ID 0608b895: NOKEY
Preparing... ########################################### [100%]
1:epel-release ########################################### [100%]
3）从指定的url中下载repofile
[root@dns1 ~]# ./load_yum_repo.sh -d http://mirrors.163.com/.help/CentOS6-Base-163.repo
--2015-04-04 22:13:47-- http://mirrors.163.com/.help/CentOS6-Base-163.repo
Resolving mirrors.163.com... 123.58.173.106
Connecting to mirrors.163.com|123.58.173.106|:80... connected.
HTTP request sent, awaiting response... 200 OK
Length: 2006 (2.0K) [application/octet-stream]
Saving to: “/etc/yum.repos.d/CentOS6-Base-163.repo”
100%[==========================================================================================>] 2,006 --.-K/s in 0.05s
2015-04-04 22:13:47 (40.9 KB/s) - “/etc/yum.repos.d/CentOS6-Base-163.repo” saved [2006/2006]
4）创建自定义的repofile
[root@dns1 ~]# ./load_yum_repo.sh -f test -n test -u file:///mnt
[root@dns1 ~]# cat /etc/yum.repos.d/test.repo
[test]
name=test
baseurl=file:///mnt
enabled=1
gpgcheck=0
Linux shell中getopts命令学习--实现一个添加yum源的脚本
原文地址：http://978538.blog.51cto.com/968538/1629016
