1. Parameter handover.
The ksh paramerter comprises $order, for example, $0, $1. The $0 means the program itself or the function itself, just like the C++, so the $1 is the first parameter, $2 second...
There are other parameter information,
$# ----传递给程序的总的参数数目
$? ----上一个代码或者shell程序在shell中退出的情况,如果正常退出则返回0,反之为非0值。
$* ----传递给程序的所有参数组成的字符串。
$n ----表示第几个参数,$1 表示第一个参数,$2 表示第二个参数 ...
$0 ----当前程序的名称
$@----以"参数1" "参数2" ... 形式保存所有参数
$$ ----本程序的(进程ID号)PID
$! ----上一个命令的PID
2. How to obtain the program option paramters.
#!/bin/bash
#getopts
ALL=false
HELP=false
FILE=false
VERBOSE=false
while getopts ahfvc: OPTION #将ahfvc依次传给OPTION c后面的:表示-c时需传入参数
do
case ${OPTION} in
a)
ALL=true
echo "ALL IS ${ALL}"
;
h)
HELP=true
echo "HELP IS ${HELP}"
;
f)
FILE=true
echo "FILE IS ${FILE}"
;
v)
VERBOS=false
echo "VERBOSE IS ${VERBOSE}"
;
c)
c=${OPTARG}
echo "c value is $c"
;
\?)
echo "`basename $0` -[a h f v] -[c value] file"
;
esac
done
输入./getopts -a 输出:ALL IS true #执行case a模式的命令
输入./getopts -h 输出:HLEP IS true #执行case h模式的命令
输入./getopts -f 输出:FILE IS true #执行case f模式的命令
输入./getopts -v 输出:VERBOSE IS true #执行case v模式的命令
输入./getopts -c 提示错误:需要传入参数 #c后面有“:”所以需传参数
输入./getopts -c hello 输出:c value is hello #执行case c模式的命令
输入./getopts -b 输出:basename ./getopts -[a h f v] -[c value] file #其他情况
3. How to compare 2 string?
The sign = is used to compare the 2 stirngs while -eq is used to compare the 2 numbers.
比较两个字符串是否相等的办法是:
if [ "$test"x = "test"x ]; then
这里的关键有几点:
1) 使用单个等号
2) 注意到等号两边各有一个空格:这是unix shell的要求
3) 注意到"$test"x最后的x,这是特意安排的,因为当$test为空的时候,上面的表达式就变成了x = testx,显然是不相等的。而如果没有这个x,表达式就会报错:[: =: unary operator expected
4) There is bank right behind [ and before ], they are necessary.
4. Simple commands.
stty erase <BackSpace> ###use the backslash as the delete key.
PS1="`/usr/ucb/whoami`@`uname -n`(KSH)[!]> " ###used to cumtomiz the command echo.
set -o vi ###set the edition mode as vi, you have the command history with that.
find . -name "test" -type f ! -newer source_test -exec cp source_test {} \; ###How to copy file when the destination file is newer file?
How to use the options parameters.
http://blog.chinaunix.net/u/5591/showart_371375.html
Please refer to the tutorial.
http://www.xxlinux.com/linux/article/unix/tigao/2006-06-24/1958.html
http://www.xxlinux.com/linux/article/unix/tigao/2006-06-24/1959.html
http://www.xxlinux.com/linux/article/unix/tigao/2006-06-24/1960.html
Ksh reference manual.
http://docs.sun.com/app/docs/doc/819-2239/ksh-1?l=en&a=view&q=ksh