Tcl只有一种语法: command arg arg ....

这种设计真的是非常好，简洁，快速！

它和很多程序设计语言不一样，它没有关键词！譬如if, switch在Tcl中也是命令。

初次体验Tcl的感觉是：利用Tcl来构建一些东西的时候，只做两件事情：一，调用命令；二，直接给参数或者用替换的方法给参数。 仅有的一种语法在有了“可替换“这个特性后，果然强大了很多！可见，好的设计，真的是至简的设计。你无法再用更少的东西来达到相同的目的了。

Tcl也是支持结构化的，比如c中的function，可以对应为Tcl中的proc(procedure的简称)。

proc procName args... {

main body

}

这样就相当于定义了一个procedure。其实，它还是个命令，这个命令做的事情的，当procName被调用时，执行mainbody.

以下给出我初步试验的脚本和结果：

#test tcl built-in commands

puts "======================start=========================="

#print "running" after 5 seconds

puts "waiting for 1 second ..."

after 1000

puts "running ..."

#append var(="Hello") with " " and "World!"

set var {}

append var "Hello" " " "World!"

puts ${var}

#test command 'for', 'if' and 'incr'

#output the odd number between [1:10]

for {set i 1} {$i <= 10} {incr i} {

if {$i%2 != 0} {puts $i}

}

#command substitution

set var [expr 1+2+3]

puts $var

#file

puts [file attributes tmp.tcl]

puts [file atime tmp.tcl]

puts [file channels *err]

puts [file dirname ~]

puts [file dirname ~/Desktop]

#file copy tmp.tcl commandtest.tcl

set flag [file executable commandtest.tcl]

if {$flag == 1} {

puts "commandtest.tcl is executable"

}

if {$flag == 0} {

puts "commandtest.tcl is not executable"

}

file mkdir testdir1 testdir2 testdir3

puts [file normalize commandtest.tcl]

puts [file separator]

#test 'proc' and 'cd'

proc mypwd args {

return [file normalize ./]

}

puts [mypwd]

set current_dir [file normalize ./]

cd /home/chenqi/Desktop

puts [mypwd]

cd ${current_dir}

puts [mypwd]

#test pwd

puts [pwd]

#test 'file stat', 'array' and 'foreach'

file stat commandtest.tcl var_stat_array

foreach {field value} [array get var_stat_array] {

puts "field: $field; value: $value"

}

puts $::tcl_platform(platform)

#test 'switch'

switch  $::tcl_platform(platform) {

unix {

puts "the platform is unix"

}

windows {

puts "the platform is windows"

}

}

#test 'exec'

puts "executing 'uname -r' command"

puts [exec uname -r]

#test time

puts [time {

puts [exec find /home/chenqi/MyPro/CFiles/ -name *.c]

}]

puts "===================end================================="

======================start==========================

waiting for 1 second ...

running ...

Hello World!

1

3

5

7

9

6

-group root -owner root -permissions 00644

1336199519

stderr

/

~

commandtest.tcl is executable

/home/chenqi/MyPro/ShellScript/tcl/commandtest.tcl

/

/home/chenqi/MyPro/ShellScript/tcl

/home/chenqi/Desktop

/home/chenqi/MyPro/ShellScript/tcl

/home/chenqi/MyPro/ShellScript/tcl

field: mtime; value: 1336203195

field: atime; value: 1336203234

field: gid; value: 0

field: nlink; value: 1

field: mode; value: 33261

field: type; value: file

field: ctime; value: 1336203195

field: uid; value: 0

field: ino; value: 2360375

field: size; value: 1724

field: dev; value: 2056

unix

the platform is unix

executing 'uname -r' command

2.6.32-21-generic

/home/chenqi/MyPro/CFiles/temp/bufsiz.c

/home/chenqi/MyPro/CFiles/Chapter-1/Hello.c

/home/chenqi/MyPro/CFiles/POSIX_Threads/autobakup.c

/home/chenqi/MyPro/CFiles/POSIX_Threads/thread1.c

/home/chenqi/MyPro/CFiles/virtual_process/virt_proc.c

/home/chenqi/MyPro/CFiles/virtual_process/test.c

/home/chenqi/MyPro/CFiles/virtual_process/hash.c

/home/chenqi/MyPro/CFiles/virtual_process/pid.c

/home/chenqi/MyPro/CFiles/IPC/semaphores/cfunc.c

/home/chenqi/MyPro/CFiles/IPC/pipes/named_pipes/client.c

/home/chenqi/MyPro/CFiles/IPC/pipes/named_pipes/server.c

/home/chenqi/MyPro/CFiles/IPC/pipes/named_pipes/tmp/procB.c

/home/chenqi/MyPro/CFiles/IPC/pipes/named_pipes/tmp/procA.c

/home/chenqi/MyPro/CFiles/IPC/pipes/named_pipes/server_with_queue.c

/home/chenqi/MyPro/CFiles/IPC/pipes/pipes_as_stdio/pipe_as_stdout.c

/home/chenqi/MyPro/CFiles/IPC/pipes/pipes_as_stdio/pipe_as_stdin.c

/home/chenqi/MyPro/CFiles/IPC/pipes/unnamed_pipes/procB.c

/home/chenqi/MyPro/CFiles/IPC/pipes/unnamed_pipes/procA.c

/home/chenqi/MyPro/CFiles/IPC/signals/test.c

/home/chenqi/MyPro/CFiles/IPC/signals/getpidbyname.c

/home/chenqi/MyPro/CFiles/IPC/signals/test2.c

/home/chenqi/MyPro/CFiles/programming-pearls/chapter1/qsort.c

/home/chenqi/MyPro/CFiles/programming-pearls/chapter1/mergesort.c

/home/chenqi/MyPro/CFiles/programming-pearls/chapter1/tmp/test.c

/home/chenqi/MyPro/CFiles/programming-pearls/chapter1/bitmap_sort.c

/home/chenqi/MyPro/CFiles/programming-pearls/chapter1/generate_random.c

4776 microseconds per iteration

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