提取文件名

ID525

爱死你们了

bikecheng

为啥没人用basename呢.

ID525

能用吗？？？

[ 本帖最后由 ID525 于 2008-7-23 12:51 编辑 ]

无声无息

原帖由 bikecheng 于 2008-7-23 12:35 发表
为啥没人用basename呢.

basename怎么用？

人家是在echo中挑。。。。。

xwmhmily

和我的想法一样,呵呵

xwmhmily

这个分隔符倒是第一次见

forlorngenius

gucuiwen

呵呵，看来会parmmeter substitution的人不是很多啊，建议好好看看

《Advanced Bash-Scripting Guide》

取前三个字符:

a="abcdefg"
echo ${a:0:3}

取后三个字符：
a="abcdefg"
echo ${a-3)}

中间三个字符:
a="abcdefg"
echo ${a:2:3}

Table B-4. Parameter Substitution and Expansion
Expression        Meaning
${var}        Value of var, same as $var
         
${var-DEFAULT}        If var not set, evaluate expression as $DEFAULT *
${varEFAULT}        If var not set or is empty, evaluate expression as $DEFAULT *
         
${var=DEFAULT}        If var not set, evaluate expression as $DEFAULT *
${var:=DEFAULT}        If var not set, evaluate expression as $DEFAULT *
         
${var+OTHER}        If var set, evaluate expression as $OTHER, otherwise as null string
${var:+OTHER}        If var set, evaluate expression as $OTHER, otherwise as null string
         
${var?ERR_MSG}        If var not set, print $ERR_MSG *
${varERR_MSG}        If var not set, print $ERR_MSG *
         
${!varprefix*}        Matches all previously declared variables beginning with varprefix
${!varprefix@}        Matches all previously declared variables beginning with varprefix

* Of course if var is set, evaluate the expression as $var.

Table B-5. String Operations
Expression        Meaning
${#string}        Length of $string
         
${string:position}        Extract substring from $string at $position
${string:position:length}        Extract $length characters substring from $string at $position
         
${string#substring}        Strip shortest match of $substring from front of $string
${string##substring}        Strip longest match of $substring from front of $string
${string%substring}        Strip shortest match of $substring from back of $string
${string%%substring}        Strip longest match of $substring from back of $string
         
${string/substring/replacement}        Replace first match of $substring with $replacement
${string//substring/replacement}        Replace all matches of $substring with $replacement
${string/#substring/replacement}        If $substring matches front end of $string, substitute $replacement for $substring
${string/%substring/replacement}        If $substring matches back end of $string, substitute $replacement for $substring
         
         
expr match "$string" '$substring'        Length of matching $substring* at beginning of $string
expr "$string" : '$substring'        Length of matching $substring* at beginning of $string
expr index "$string" $substring        Numerical position in $string of first character in $substring that matches
expr substr $string $position $length        Extract $length characters from $string starting at $position
expr match "$string" '\($substring\)'        Extract $substring* at beginning of $string
expr "$string" : '\($substring\)'        Extract $substring* at beginning of $string
expr match "$string" '.*\($substring\)'        Extract $substring* at end of $string
expr "$string" : '.*\($substring\)'        Extract $substring* at end of $string

Shell_HAT

期待你的basename版本的

Shell_HAT

如果文件名里面的字符位数不确定怎么办？