脚本语言TCL教程:5

1.1 ：文件存取

1． 文件打开命令：

格式：openfile fileName ? access ? permission

解释：

Ø fileName：文件名称

Ø access：存取模式

Ø permission：权限，举一个例子：

1.2 ：文件信息

1．File命令提供文件信息

2．glob命令通过匹配模式返回一个文件名列表

格式：glob ?switches? pattern? patternN?

Ø switches：

-nocomplain：允许返回一个空列表的时候不生成错误，如果没有这个开关，返回空列表的时候会生成错误

--：允许在匹配式中使用横杠

Ø pattern：匹配式

l {a,b,....}：匹配所有的a，b，等字符串

l 文件名以小数点开头则解析为小数点，其他地方就解析为通配符；

l 所有的 / 都必须准确匹配；

l 如果匹配式开始是：~/ ，则 ~ 解析为环境变量HOME；

1.3 如果匹配式的：TCL中的子进程调用－open & exec

1． 格式：open |progName ?access?

功能：为管道返回一个文件描述符。如果progName用引号括起来，可以包含参数。

2． 格式：exec ?switches?arg1?arg2?....?argN?

功能：执行子进程

Ø switches：-keepnewline：管道输出的每行后面加个新行。

-- ：标志开关结束，哪怕后面跟着有 – 开头的字符串，都作为参数处理。

Ø argN：参数可以是：可执行程序；作为子进程运行的命令行；输出重定向

输出重定向包含有：

例子：027_file.txt

set io [open "|c:/windows/system32/notepad.exe c:/temp/inv_2700.tcl" r+] ;#open 调用外部程序

set invert [exec c:/windows/system32/notepad.exe c:/temp/001.txt] ;#exec 调用外部程序

因为管道的例子在windows下比较难举，现以unix下一段代码为例子，通过管道读出 ps(列出进程)命令的输出

tclfolder%tclsh

% set fid [open "|ps -ef" r+]

file5

% gets $fid line;puts "line: $line"

line: UID PID PPID C STIME TTY TIME CMD

% gets $fid line;puts "line: $line"

line: root 1 0 0 Nov 11 - 0:01 /etc/init

% gets $fid line;puts "line: $line"

line: root 86118 1 0 Nov 11 - 5:00 /usr/sbin/syncd 60

% gets $fid line;puts "line: $line"

line: tclll 90248 893094 0 11:54:55 pts/14 0:00 -csh

% gets $fid line;puts "line: $line"

line: root 110730 1 0 Nov 11 - 0:00 /usr/sbin/uprintfd

% gets $fid line;puts "line: $line"

line: root 118848 1 0 Nov 11 - 0:00 /usr/ccs/bin/shlap64

% exit

tclfolder%

1.4 ：命令或者变量是否存在－info

1． info命令列表，使用的匹配式规则和string match一致，并且如果不使用匹配式，返回所有的项

例子：028_file.tcl

proc safeIncr {val {amt 1}} {

upvar $val v

if {[info exists v]} { incr v $amt} else { set v $amt }

}

if {[info procs safeIncr] == "safeIncr"} { ;#判断过程是否定义

safeIncr a ;#a 没有定义

}

puts "After calling SafeIncr with a non existent variable: $a" ;#返回1

set a 100

safeIncr a

puts "After calling SafeIncr with a variable with a value of 100: $a" ;#返回101

safeIncr b -3

puts "After calling safeIncr with a non existent variable by -3: $b" ;#返回-3

set b 100

safeIncr b -3

puts "After calling safeIncr with a variable whose value is 100 by -3: $b" ;#返回97

puts "\nThese variables have been defined: [lsort [info vars]]"

puts "\nThese globals have been defined: [lsort [info globals]]"

;# 检查本地过程是否存在

set exist [info procs localproc];

if {$exist == ""} {

puts "\nlocalproc does not exist at point 1"

}

proc localproc {} {

global argv;

set loc1 1;

set loc2 2;

puts "\nLocal variables accessible in this proc are: [lsort [info locals]]"

puts "\nVariables accessible from this proc are: [lsort [info vars]]"

puts "\nGlobal variables visible from this proc are: [lsort [info globals]]"

}

set exist [info procs localproc];

if {$exist != ""} {

puts "localproc does exist at point 2"

}

localproc;

1.5 ：解释器状态－info

1． 关于当前解释器状态信息命令列表

例子：029_file.tcl

puts "This is how many commands have been executed: [info cmdcount]"

puts "Now *THIS* many commands have been executed: [info cmdcount]"

puts "\nThis interpreter is revision level: [info tclversion]"

puts "This interpreter is at patch level: [info patchlevel]"

puts "\nThe temporary script this is executing is named: [info script]"

puts "The Pid for this program is [pid]"

proc factorial {val} {

puts "Current level: [info level] - val: $val"

set lvl [info level]

if {$lvl == $val} {return $val;}

return [expr ($val-$lvl) * [factorial $val]];

}

set count1 [info cmdcount]

set fact [factorial 3]

set count2 [info cmdcount]

puts "The factorial of 3 is $fact"

puts "Before calling the factorial proc, $count1 commands had been executed"

puts "After calling the factorial proc, $count2 commands had been executed"

puts "It took [expr $count2-$count1] commands to calculate this factorial"

1.6 ：过程信息－info

1．关于过程信息的命令列表

例子：030_procinfo.tcl

proc demo {argument1 {default "DefaultValue"} } {

puts "This is a demo proc. It is being called with $argument1 and $default"

}

puts "The args for demo are: [info args demo]\n"

puts "The body for demo is: [info body demo]\n"

set arglist [info args demo]

foreach arg $arglist {

if {[info default demo $arg defaultval]} { ;#defaultval 用于取回缺省值

puts "$arg has a default value of $defaultval"

} else {

puts "$arg has no default"

}

}