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工作学习 / IT技术讨论 / Sailor和Egg，看你们“啊”得这么起劲，来回答我的问题：为什么echo \\和echo \\\\的结果都是\，echo \\\\\\和echo \\\\\\\\的结果都是\\，而echo \\\\\\\\\\和echo \\\\\\\\\\\\的结果都是\\\呢？
-pasu(InTheSky);
2001-4-26
(#54451@0)
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Is it from Unix/Linux? Don't tell me it is from Dos/Windows.
-guest:;
2001-4-26
(#54456@0)
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Bourne Shell
-pasu(InTheSky);
2001-4-26
(#54458@0)
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numnum? any body?
-pasu(InTheSky);
2001-4-26
(#54469@0)
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后边的那些都被忽略了
-shou(小受);
2001-4-26
(#54473@0)
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Detail! From which?
-pasu(InTheSky);
2001-4-26
(#54477@0)
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只有idiot才研究这种问题。in shell, \\ = \? sorry, I'm a idiot on UNIX.
-eglington(eglington);
2001-4-26
(#54476@0)
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Explain again: echo 2 \ and 4 \ get 1 \; echo 6 \ and 8 \ get 2 \; echo 10 \ and 12 \ get 3 \. Why?
-pasu(InTheSky);
2001-4-26
(#54483@0)
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The backslash is intepreted by shell. \\=\. I got 4 \ when I put 8 \ on tcsh. I am glad to talk about it further with you.
-chengyu(Chuan);
2001-4-26
(#54502@0)
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Thx! I know \\ = \. But I was really puzzled by so many \'s lined up.
-pasu(InTheSky);
2001-4-26
(#54516@0)
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don't know,,, you are a weird guy, always studying weird problems. hehe
-numnum(numnum);
2001-4-26
(#54489@0)
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Help me. At least explain why echo \\ and echo \\\\ are both producing \?
-pasu(InTheSky);
2001-4-26
(#54512@0)
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okay, I already know why, any prize?
-numnum(numnum);
2001-4-26
(#54517@0)
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I will go to watch how do you put the ring on lumlum's finger. xixi.
-pasu(InTheSky);
2001-4-26
(#54522@0)
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be patient, I am writing the answer, it's a bit complicated to explain all this
-numnum(numnum);
2001-4-26
(#54529@0)
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NP&THX
-pasu(InTheSky);
2001-4-26
(#54531@0)
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me too.
-lumlumq(lumlum);
2001-4-26
(#54533@0)
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be patient. he's working for the answer. it's a bit complicated to work out the whole thing. hehe.
-pasu(InTheSky);
2001-4-26
(#54539@0)
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不行啦，我肚子笑得要抽筋啦……
-bxy(西岭);
2001-4-26
(#54545@0)
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Why do you laugh at a guy he is really serious about romance? Do not laugh, just be patient.
-guest:;
2001-4-26
(#54610@0)
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?
-bxy(西岭);
2001-4-26
(#54670@0)
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There are two layers of escape you need to consider: shell itself, and echo program
-numnum(numnum);
2001-4-26
{1382}
(#54551@0)
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THX! The key to me is :"Echo has a peculiar behavior that when it encounters a single "\" who doesn't have anybody else to escape, it will print out "\" anyway. " I know the rest. And I did not ask this question for fun.Cuz I wrote below statement in my script:
sed s/\\\\//\\\\\\\\\\\\//g tmpfile
And I was really puzzled when I tune this script. I had to try many times to get the correct form.
hehe...What's more, do you know what did I want to do with the statement above?
-pasu(InTheSky);
2001-4-26
{282}
(#54557@0)
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嘿嘿，你整天就搞些怪东西， 你用nawk应该会好多了
-lumlumq(lumlum);
2001-4-26
(#54571@0)
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awk要调解释器，麻烦，而且运行级别低的时候不能用。而且个人认为awk的长处是做运算和有比较复杂流程的任务，比方说处理log之类的；文本处理还是用ed、sed和tr比较爽。虽然regexp比较晦涩，但是其实很好用；喜欢摆弄它就象有的人喜欢开手动档的汽车一样。不过可惜还没玩熟，而且还老容易忘。
-pasu(InTheSky);
2001-4-26
{34}
(#54591@0)
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exactly.
-guest:;
2001-4-26
(#54606@0)
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awk is almost as simple as sed, you can put the script directly in the command line. It has a much more complete set of utilities, sometimes it is viewed as a programming language, like perl.Actully, I only use sed as "sed -n "s/***/88/g" " because it already beomes a habit.
-numnum(numnum);
2001-4-27
{88}
(#55208@0)
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Yes, awk is a script language indeed. It's the very reason I don't want to use it to deal with the text. You know, you will have to almost re-write a part of sed, ed or tr. Why not use a provided utillity?
-pasu(InTheSky);
2001-4-27
(#55359@0)
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BTW, How did you know the stupid feature of echo? I cannot get it from man page. Is there any document for it?
-pasu(InTheSky);
2001-4-27
(#54632@0)
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感觉啦，如果只有一个”\”，他ESCAPE谁去啊？但你不能就这么忽视它巴，这些东西很多都是COMMON的。 后来写程序时候，
用execlp()把ECHO绕过SHELL调用了一下，证明是这样。 好了，要上班去啦。。。呵呵，等会再聊
-numnum(numnum);
2001-4-27
(#55154@0)
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我还以为你看过source code呢，呵呵。Thx!
-pasu(InTheSky);
2001-4-27
(#55168@0)
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heihei, I'm in the office now, just got a cup of coffee. Echo's source code should be really simple, I have written some kind of regular expression library for real time system, it's common sense how to interpret certain things.
-numnum(numnum);
2001-4-27
(#55195@0)
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Obviously it's common to you programmers. hehe...
-pasu(InTheSky);
2001-4-27
(#55348@0)