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-rw-r--r--zh-cn/awk-cn.html.markdown277
1 files changed, 120 insertions, 157 deletions
diff --git a/zh-cn/awk-cn.html.markdown b/zh-cn/awk-cn.html.markdown
index fcd17b4f..1fafa559 100644
--- a/zh-cn/awk-cn.html.markdown
+++ b/zh-cn/awk-cn.html.markdown
@@ -8,41 +8,35 @@ filename: learnawk-cn.awk
lang: zh-cn
---
-AWK is a standard tool on every POSIX-compliant UNIX system. It's like a
-stripped-down Perl, perfect for text-processing tasks and other scripting
-needs. It has a C-like syntax, but without semicolons, manual memory
-management, or static typing. It excels at text processing. You can call to it
-from a shell script, or you can use it as a stand-alone scripting language.
-
-Why use AWK instead of Perl? Mostly because AWK is part of UNIX. You can always
-count on it, whereas Perl's future is in question. AWK is also easier to read
-than Perl. For simple text-processing scripts, particularly ones that read
-files line by line and split on delimiters, AWK is probably the right tool for
-the job.
+AWK是POSIX兼容的UNIX系统中的标准工具. 它像简化版的Perl, 非常适用于文本处理任务和其他脚本类需求.
+它有着C风格的语法, 但是没有分号, 没有手动内存管理, 没有静态类型.
+他擅长于文本处理, 你可以通过shell脚本调用AWK, 也可以用作独立的脚本语言.
+
+为什么使用AWK而不是Perl, 大概是因为AWK是UNIX的一部分, 你总能依靠它, 而Perl已经前途未卜了.
+AWK比Perl更易读. 对于简单的文本处理脚本, 特别是按行读取文件, 按分隔符分隔处理, AWK极可能是正确的工具.
```awk
#!/usr/bin/awk -f
-# Comments are like this
+# 注释使用井号
-# AWK programs consist of a collection of patterns and actions. The most
-# important pattern is called BEGIN. Actions go into brace blocks.
+# AWK程序由一系列 模式(patterns) 和 动作(actions) 组成.
+# 最重要的模式叫做 BEGIN. 动作由大括号包围.
BEGIN {
- # BEGIN will run at the beginning of the program. It's where you put all
- # the preliminary set-up code, before you process any text files. If you
- # have no text files, then think of BEGIN as the main entry point.
+ # BEGIN在程序最开始运行. 在这里放一些在真正处理文件之前的准备和setup的代码.
+ # 如果没有文本文件要处理, 那就把BEGIN作为程序的主入口吧.
- # Variables are global. Just set them or use them, no need to declare..
+ # 变量是全局的. 直接赋值使用即可, 无需声明.
count = 0
- # Operators just like in C and friends
+ # 运算符和C语言系一样
a = count + 1
b = count - 1
c = count * 1
- d = count / 1 # integer division
- e = count % 1 # modulus
- f = count ^ 1 # exponentiation
+ d = count / 1 # 整数除法
+ e = count % 1 # 取余
+ f = count ^ 1 # 取幂
a += 1
b -= 1
@@ -51,26 +45,26 @@ BEGIN {
e %= 1
f ^= 1
- # Incrementing and decrementing by one
+ # 自增1, 自减1
a++
b--
- # As a prefix operator, it returns the incremented value
+ # 前置运算, 返回增加之后的值
++a
--b
- # Notice, also, no punctuation such as semicolons to terminate statements
+ # 注意, 不需要分号之类的标点来分隔语句
- # Control statements
+ # 控制语句
if (count == 0)
print "Starting with count of 0"
else
print "Huh?"
- # Or you could use the ternary operator
+ # 或者三目运算符
print (count == 0) ? "Starting with count of 0" : "Huh?"
- # Blocks consisting of multiple lines use braces
+ # 多行的代码块用大括号包围
while (a < 10) {
print "String concatenation is done" " with a series" " of"
" space-separated strings"
@@ -82,126 +76,118 @@ BEGIN {
for (i = 0; i < 10; i++)
print "Good ol' for loop"
- # As for comparisons, they're the standards:
- a < b # Less than
- a <= b # Less than or equal
- a != b # Not equal
- a == b # Equal
- a > b # Greater than
- a >= b # Greater than or equal
+ # 标准的比较运算符
+ a < b # 小于
+ a <= b # 小于或等于
+ a != b # 不等于
+ a == b # 等于
+ a > b # 大于
+ a >= b # 大于或等于
- # Logical operators as well
- a && b # AND
- a || b # OR
+ # 也有逻辑运算符
+ a && b # 且
+ a || b # 或
- # In addition, there's the super useful regular expression match
+ # 并且有超实用的正则表达式匹配
if ("foo" ~ "^fo+$")
print "Fooey!"
if ("boo" !~ "^fo+$")
print "Boo!"
- # Arrays
+ # 数组
arr[0] = "foo"
arr[1] = "bar"
- # Unfortunately, there is no other way to initialize an array. Ya just
- # gotta chug through every value line by line like that.
+ # 不幸的是, 没有其他方式初始化数组. 必须像这样一行一行的赋值.
- # You also have associative arrays
+ # 关联数组, 类似map或dict的用法.
assoc["foo"] = "bar"
assoc["bar"] = "baz"
- # And multi-dimensional arrays, with some limitations I won't mention here
+ # 多维数组. 但是有一些局限性这里不提了.
multidim[0,0] = "foo"
multidim[0,1] = "bar"
multidim[1,0] = "baz"
multidim[1,1] = "boo"
- # You can test for array membership
+ # 可以检测数组包含关系
if ("foo" in assoc)
print "Fooey!"
- # You can also use the 'in' operator to traverse the keys of an array
+ # 可以使用in遍历数组
for (key in assoc)
print assoc[key]
- # The command line is in a special array called ARGV
+ # 命令行参数是一个叫ARGV的数组
for (argnum in ARGV)
print ARGV[argnum]
- # You can remove elements of an array
- # This is particularly useful to prevent AWK from assuming the arguments
- # are files for it to process
+ # 可以从数组中移除元素
+ # 在 防止awk把文件参数当做数据来处理 时delete功能很有用.
delete ARGV[1]
- # The number of command line arguments is in a variable called ARGC
+ # 命令行参数的个数是一个叫ARGC的变量
print ARGC
- # AWK has several built-in functions. They fall into three categories. I'll
- # demonstrate each of them in their own functions, defined later.
+ # AWK有很多内置函数, 分为三类, 会在接下来定义的各个函数中介绍.
return_value = arithmetic_functions(a, b, c)
string_functions()
io_functions()
}
-# Here's how you define a function
+# 定义函数
function arithmetic_functions(a, b, c, d) {
- # Probably the most annoying part of AWK is that there are no local
- # variables. Everything is global. For short scripts, this is fine, even
- # useful, but for longer scripts, this can be a problem.
+ # 或许AWK最让人恼火的地方是没有局部变量, 所有东西都是全局的,
+ # 对于短的脚本还好, 对于长一些的就会成问题.
- # There is a work-around (ahem, hack). Function arguments are local to the
- # function, and AWK allows you to define more function arguments than it
- # needs. So just stick local variable in the function declaration, like I
- # did above. As a convention, stick in some extra whitespace to distinguish
- # between actual function parameters and local variables. In this example,
- # a, b, and c are actual parameters, while d is merely a local variable.
+ # 这里有一个技巧, 函数参数是对函数局部可见的, 并且AWK允许定义多余的参数,
+ # 因此可以像上面那样把局部变量插入到函数声明中.
+ # 为了方便区分普通参数(a,b,c)和局部变量(d), 可以多键入一些空格.
- # Now, to demonstrate the arithmetic functions
+ # 现在介绍数学类函数
- # Most AWK implementations have some standard trig functions
+ # 多数AWK实现中包含标准的三角函数
localvar = sin(a)
localvar = cos(a)
localvar = atan2(a, b) # arc tangent of b / a
- # And logarithmic stuff
+ # 对数
localvar = exp(a)
localvar = log(a)
- # Square root
+ # 平方根
localvar = sqrt(a)
- # Truncate floating point to integer
+ # 浮点型转为整型
localvar = int(5.34) # localvar => 5
- # Random numbers
- srand() # Supply a seed as an argument. By default, it uses the time of day
- localvar = rand() # Random number between 0 and 1.
+ # 随机数
+ srand() # 接受随机种子作为参数, 默认使用当天的时间
+ localvar = rand() # 0到1之间随机
- # Here's how to return a value
+ # 函数返回
return localvar
}
function string_functions( localvar, arr) {
- # AWK, being a string-processing language, has several string-related
- # functions, many of which rely heavily on regular expressions.
+ # AWK, 作为字符处理语言, 有很多字符串相关函数, 其中大多数都严重依赖正则表达式.
- # Search and replace, first instance (sub) or all instances (gsub)
- # Both return number of matches replaced
+ # 搜索并替换, 第一个出现的 (sub) or 所有的 (gsub)
+ # 都是返回替换的个数
localvar = "fooooobar"
sub("fo+", "Meet me at the ", localvar) # localvar => "Meet me at the bar"
gsub("e+", ".", localvar) # localvar => "m..t m. at th. bar"
- # Search for a string that matches a regular expression
- # index() does the same thing, but doesn't allow a regular expression
- match(localvar, "t") # => 4, since the 't' is the fourth character
+ # 搜索匹配正则的字符串
+ # index() 也是搜索, 不支持正则
+ match(localvar, "t") # => 4, 't'在4号位置. (译者注: awk是1开始计数的,不是常见的0-base)
- # Split on a delimiter
+ # 按分隔符分隔
split("foo-bar-baz", arr, "-") # a => ["foo", "bar", "baz"]
- # Other useful stuff
+ # 其他有用的函数
sprintf("%s %d %d %d", "Testing", 1, 2, 3) # => "Testing 1 2 3"
substr("foobar", 2, 3) # => "oob"
substr("foobar", 4) # => "bar"
@@ -212,99 +198,81 @@ function string_functions( localvar, arr) {
function io_functions( localvar) {
- # You've already seen print
+ # 你已经见过的print函数
print "Hello world"
- # There's also printf
+ # 也有printf
printf("%s %d %d %d\n", "Testing", 1, 2, 3)
- # AWK doesn't have file handles, per se. It will automatically open a file
- # handle for you when you use something that needs one. The string you used
- # for this can be treated as a file handle, for purposes of I/O. This makes
- # it feel sort of like shell scripting:
-
+ # AWK本身没有文件句柄, 当你使用需要文件的东西时会自动打开文件, 做文件I/O时, 字符串就是打开的文件句柄.
+ # 这看起来像Shell
print "foobar" >"/tmp/foobar.txt"
- # Now the string "/tmp/foobar.txt" is a file handle. You can close it:
+ # 现在"/tmp/foobar.txt"字符串是一个文件句柄, 你可以关闭它
close("/tmp/foobar.txt")
- # Here's how you run something in the shell
+ # 在shell里运行一些东西
system("echo foobar") # => prints foobar
- # Reads a line from standard input and stores in localvar
+ # 从标准输入中读一行, 并存储在localvar中
getline localvar
- # Reads a line from a pipe
+ # 从管道中读一行, 并存储在localvar中
"echo foobar" | getline localvar # localvar => "foobar"
close("echo foobar")
- # Reads a line from a file and stores in localvar
+ # 从文件中读一行, 并存储在localvar中
getline localvar <"/tmp/foobar.txt"
close("/tmp/foobar.txt")
}
-# As I said at the beginning, AWK programs consist of a collection of patterns
-# and actions. You've already seen the all-important BEGIN pattern. Other
-# patterns are used only if you're processing lines from files or standard
-# input.
-#
-# When you pass arguments to AWK, they are treated as file names to process.
-# It will process them all, in order. Think of it like an implicit for loop,
-# iterating over the lines in these files. these patterns and actions are like
-# switch statements inside the loop.
+# 正如开头所说, AWK程序由一系列模式和动作组成. 你已经看见了重要的BEGIN pattern,
+# 其他的pattern在你需要处理来自文件或标准输入的的数据行时才用到.
+#
+# 当你给AWK程序传参数时, 他们会被视为要处理文件的文件名, 按顺序全部会处理.
+# 可以把这个过程看做一个隐式的循环, 遍历这些文件中的所有行.
+# 然后这些模式和动作就是这个循环里的switch语句一样
/^fo+bar$/ {
- # This action will execute for every line that matches the regular
- # expression, /^fo+bar$/, and will be skipped for any line that fails to
- # match it. Let's just print the line:
-
+ # 这个动作会在匹配这个正则(/^fo+bar$/)的每一行上执行. 不匹配的则会跳过.
+ # 先让我们打印它:
print
- # Whoa, no argument! That's because print has a default argument: $0.
- # $0 is the name of the current line being processed. It is created
- # automatically for you.
+ # 哦, 没有参数, 那是因为print有一个默认参数 $0.
+ # $0 是当前正在处理的行, 自动被创建好了.
- # You can probably guess there are other $ variables. Every line is
- # implicitly split before every action is called, much like the shell
- # does. And, like the shell, each field can be access with a dollar sign
+ # 你可能猜到有其他的$变量了.
+ # 每一行在动作执行前会被分隔符分隔. 像shell中一样, 每个字段都可以用$符访问
- # This will print the second and fourth fields in the line
+ # 这个会打印这行的第2和第4个字段
print $2, $4
- # AWK automatically defines many other variables to help you inspect and
- # process each line. The most important one is NF
-
- # Prints the number of fields on this line
+ # AWK自动定义了许多其他的变量帮助你处理行. 最常用的是NF变量
+ # 打印这一行的字段数
print NF
- # Print the last field on this line
+ # 打印这一行的最后一个字段
print $NF
}
-# Every pattern is actually a true/false test. The regular expression in the
-# last pattern is also a true/false test, but part of it was hidden. If you
-# don't give it a string to test, it will assume $0, the line that it's
-# currently processing. Thus, the complete version of it is this:
+# 每一个模式其实是一个true/false判断, 上面那个正则其实也是一个true/false判断, 只不过被部分省略了.
+# 没有指定时默认使用当前处理的整行($0)进行匹配. 因此, 完全版本是这样:
$0 ~ /^fo+bar$/ {
print "Equivalent to the last pattern"
}
a > 0 {
- # This will execute once for each line, as long as a is positive
+ # 只要a是整数, 这块会在每一行上执行.
}
-# You get the idea. Processing text files, reading in a line at a time, and
-# doing something with it, particularly splitting on a delimiter, is so common
-# in UNIX that AWK is a scripting language that does all of it for you, without
-# you needing to ask. All you have to do is write the patterns and actions
-# based on what you expect of the input, and what you want to do with it.
+# 就是这样, 处理文本文件, 一次读一行, 对行做一些操作. 按分隔符分隔, 这在UNIX中很常见, awk都帮你做好了.
+# 你所需要做的是基于自己的需求写一些模式和动作.
-# Here's a quick example of a simple script, the sort of thing AWK is perfect
-# for. It will read a name from standard input and then will print the average
-# age of everyone with that first name. Let's say you supply as an argument the
-# name of a this data file:
+# 这里有一个快速的例子, 展示了AWK所擅长做的事.
+# 它从标准输入读一个名字, 打印这个first name下所有人的平均年龄.
+# 示例数据:
#
# Bob Jones 32
# Jane Doe 22
@@ -312,41 +280,36 @@ a > 0 {
# Bob Smith 29
# Bob Barker 72
#
-# Here's the script:
+# 示例脚本:
BEGIN {
- # First, ask the user for the name
+ # 首先, 问用户要一个名字
print "What name would you like the average age for?"
- # Get a line from standard input, not from files on the command line
+ # 从标准输入获取名字
getline name <"/dev/stdin"
}
-# Now, match every line whose first field is the given name
+# 然后, 用给定的名字匹配每一行的第一个字段.
$1 == name {
- # Inside here, we have access to a number of useful variables, already
- # pre-loaded for us:
- # $0 is the entire line
- # $3 is the third field, the age, which is what we're interested in here
- # NF is the number of fields, which should be 3
- # NR is the number of records (lines) seen so far
- # FILENAME is the name of the file being processed
- # FS is the field separator being used, which is " " here
- # ...etc. There are plenty more, documented in the man page.
-
- # Keep track of a running total and how many lines matched
+ # 这里我们要使用几个有用的变量, 已经提前为我们加载好的:
+ # $0 是整行
+ # $3 是第三个字段, 就是我们所感兴趣的年龄
+ # NF 字段数, 这里是3
+ # NR 至此为止的行数
+ # FILENAME 在处理的文件名
+ # FS 在使用的字段分隔符, 这里是空格" "
+ # ...等等, 还有很多, 在帮助文档中列出.
+
+ # 跟踪 总和以及行数
sum += $3
nlines++
}
-# Another special pattern is called END. It will run after processing all the
-# text files. Unlike BEGIN, it will only run if you've given it input to
-# process. It will run after all the files have been read and processed
-# according to the rules and actions you've provided. The purpose of it is
-# usually to output some kind of final report, or do something with the
-# aggregate of the data you've accumulated over the course of the script.
+# 另一个特殊的模式叫END. 它会在处理完所有行之后运行. 不像BEGIN, 它只会在有输入的时候运行.
+# 它在所有文件依据给定的模式和动作处理完后运行, 目的通常是输出一些最终报告, 做一些数据聚合操作.
END {
if (nlines)
@@ -354,8 +317,8 @@ END {
}
```
-Further Reading:
+更多:
-* [Awk tutorial](http://www.grymoire.com/Unix/Awk.html)
-* [Awk man page](https://linux.die.net/man/1/awk)
-* [The GNU Awk User's Guide](https://www.gnu.org/software/gawk/manual/gawk.html) GNU Awk is found on most Linux systems.
+* [Awk 教程](http://www.grymoire.com/Unix/Awk.html)
+* [Awk 手册](https://linux.die.net/man/1/awk)
+* [The GNU Awk 用户指南](https://www.gnu.org/software/gawk/manual/gawk.html) GNU Awk在大多数Linux中预装