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ksh 实现的基于hpux下的性能数据以及故障的采集程序。可以作为新手练手使用

 ksh(1)								      ksh(1)




 NAME
      ksh, rksh - shell, the standard/restricted command programming
      language

 SYNOPSIS
      ksh [-aefhikmnoprstuvx] [+aefhikmnoprstuvx] [-o option] ...  [+o
      option] ...  [-c string] [arg ...]

      rksh [-aefhikmnoprstuvx] [+aefhikmnoprstuvx] [-o option] ...  [+o
      option] ...  [-c string] [arg ...]

 DESCRIPTION
      ksh is a command programming language that executes commands read from
      a terminal or a file.  rksh is a restricted version of the command
      interpreter ksh, used to set up login names and execution environments
      whose capabilities are more controlled than those of the standard
      shell.  See Invoking ksh and Special Commands sections later in this
      entry for details about command line options and arguments,
      particularly the set command.

    Definitions
      metacharacter  One of the following characters:

		     ;	 &   (	 )   |	 <   >	 new-line   space   tab

      blank	     A tab or space character.

      identifier     A sequence of letters, digits, or underscores starting
		     with a letter or underscore.  Identifiers are used as
		     names for functions and named parameters.

      word	     A sequence of characters separated by one or more non-
		     quoted metacharacters .

      command	     A sequence of characters in the syntax of the shell
		     language.	The shell reads each command and carries out
		     the desired action, either directly or by invoking
		     separate utilities.

      special command
		     A command that is carried out by the shell without
		     creating a separate process.  Often called ``built-in
		     commands''.  Except for documented side effects, most
		     special commands can be implemented as separate
		     utilities.

      #		     The # character is interpreted as the beginning of a
		     comment.  See Quoting below.

    Commands
      A simple-command is a sequence of blank-separated words that can be



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      preceded by a parameter assignment list.	(See Environment below).
      The first word specifies the name of the command to be executed.
      Except as specified below, the remaining words are passed as arguments
      to the invoked command.  The command name is passed as argument 0 (see
      exec(2)).	 The value of a simple-command is its exit status if it
      terminates normally, or (octal) 200+status if it terminates abnormally
      (see signal(5) for a list of status values).

      A pipeline is a sequence of one or more commands separated by |.	The
      standard output of each command except the last is connected by a pipe
      (see pipe(2)) to the standard input of the next command.	Each command
      is run as a separate process; the shell waits for the last command to
      terminate.  The exit status of a pipeline is the exit status of the
      last command in the pipeline.

      A list is a sequence of one or more pipelines separated by ;, &, &&,
      or ||, and optionally terminated by ;, &, or |&.	Of these five
      symbols, ;, &, and |& have equal precedence.  && and || have a higher
      but also equal precedence.  A semicolon (;) causes sequential
      execution of the preceding pipeline; an ampersand (&) causes
      asynchronous execution of the preceding pipeline (that is, the shell
      does not wait for that pipeline to finish).  The symbol |& causes
      asynchronous execution of the preceding command or pipeline with a
      two-way pipe established to the parent shell (known as a co-process).
      The standard input and output of the spawned command can be written to
      and read from by the parent shell using the -p option of the special
      commands read and print described later.	The symbol && (||) causes
      the list following it to be executed only if the preceding pipeline
      returns a zero (non-zero) value.	An arbitrary number of new-lines can
      appear in a list, instead of semicolons, to delimit commands.

      A command is either a simple-command or one of the following.  Unless
      otherwise stated, the value returned by a command is that of the last
      simple-command executed in the command.

      for identifier [in word ...] do list done
		     Each time for is executed, identifier is set to the
		     next word taken from the in word list.  If in word ...
		     is omitted, for executes the do list once for each
		     positional parameter set (see Parameter Substitution
		     below).  Execution ends when there are no more words in
		     the list.

      select identifier [in word...] do list done
		     A select command prints on standard error (file
		     descriptor 2), the set of words, each preceded by a
		     number.  If in word ...  is omitted, the positional
		     parameters are used instead (see Parameter Substitution
		     below).  The PS3 prompt is printed and a line is read
		     from the standard input.  If this line starts with the
		     number of one of the listed words, the value of the



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		     parameter identifier is set to the word corresponding
		     to this number.  If this line is empty, the selection
		     list is printed again.  Otherwise the value of the
		     parameter identifier is set to null.  The contents of
		     the line read from standard input is saved in the
		     parameter REPLY.  The list is executed for each
		     selection until a break or end-of-file (eof) is
		     encountered.

      case word in [[ (] pattern [ | pattern] ... ) list ;; ] ... esac
		     A case command executes the list associated with the
		     first pattern that matches word.  The form of the
		     patterns is identical to that used for file name
		     generation (see File Name Generation below).

      if list then list [ elif list then list] ... [ else list] fi
		     The list following if is executed and, if it returns a
		     zero exit status, the list following the first then is
		     executed.	Otherwise, the list following elif is
		     executed and, if its value is zero, the list following
		     the next then is executed.	 Failing that, the else list
		     is executed.  If no else list or then list is executed,
		     if returns a zero exit status.

      while list do list done
      until list do list done
		     A while command repeatedly executes the while list, and
		     if the exit status of the last command in the list is
		     zero, executes the do list; otherwise the loop
		     terminates.  If no commands in the do list are
		     executed, while returns a zero exit status; until can
		     be used in place of while to negate the loop
		     termination test.

      (list)	     Execute list in a separate environment.  If two
		     adjacent open parentheses are needed for nesting, a
		     space must be inserted to avoid arithmetic evaluation
		     as described below.

      { list;}	     Execute list, but not in a separate environment.  Note
		     that { is a keyword and requires a trailing blank to be
		     recognized.

      [[ expression ]]
		     Evaluates expression and returns a zero exit status
		     when expression is true.  See Conditional Expressions
		     below, for a description of expression.  Note that [[
		     and ]] are keywords and require blanks between them and
		     expression.





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      function identifier {list;}
      identifier () {list;}
		     Define a function referred to by identifier.  The body
		     of the function is the list of commands between { and }
		     (see Functions below).

      time pipeline  pipeline is executed and the elapsed time, user time,
		     and system time are printed on standard error. Note
		     that the time keyword can appear anywhere in the
		     pipeline to time the entire pipeline. To time a
		     particular command in a pipeline, see time(1).

      The following keywords are recognized only as the first word of a
      command and when not quoted:

	   if then else elif fi case esac for while
	   until do done { } function select time [[ ]]

    Comments
      A word beginning with # causes that word and all subsequent characters
      up to a new-line to be ignored.

    Aliasing
      The first word of each command is replaced by the text of an alias, if
      an alias for this word has been defined.	An alias name consists of
      any number of characters excluding metacharacters, quoting characters,
      file expansion characters, parameter and command substitution
      characters, and =.  The replacement string can contain any valid shell
      script, including the metacharacters listed above.  The first word of
      each command in the replaced text, other than any that are in the
      process of being replaced, is tested for additional aliases.  If the
      last character of the alias value is a blank, the word following the
      alias is also checked for alias substitution.  Aliases can be used to
      redefine special built-in commands, but cannot be used to redefine the
      keywords listed above.  Aliases can be created, listed, and exported
      with the alias command and can be removed with the unalias command.
      Exported aliases remain in effect for subshells but must be
      reinitialized for separate invocations of the shell (see Invoking ksh
      below).

      Aliasing is performed when scripts are read, not while they are
      executed.	 Therefore, for it to take effect, alias must be executed
      before the command referring to the alias is read.

      Aliases are frequently used as a shorthand for full path names.  An
      option to the aliasing facility allows the value of the alias to be
      automatically set to the full path name of the corresponding command.
      These aliases are called tracked aliases.	 The value of a tracked
      alias is defined the first time the identifier is read and becomes
      undefined each time the PATH variable is reset.  These aliases remain
      tracked so that the next reference redefines the value.  Several



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      tracked aliases are compiled into the shell.  The -h option of the set
      command converts each command name that is an identifier into a
      tracked alias.

      The following exported aliases are compiled into the shell but can be
      unset or redefined:

	   autoload='typeset -fu'
	   false='let 0'
	   functions='typeset -f'
	   hash='alias -t -'
	   history='fc -l'
	   integer='typeset -i'
	   nohup='nohup '
	   r='fc -e -'
	   stop='kill -STOP'
	   suspend='kill -STOP $$'
	   true=':'
	   type='whence -v'

    Tilde Substitution
      After alias substitution is performed, each word is checked to see if
      it begins with an unquoted ~.  If it does, the word up to a / is
      checked to see if it matches a user name in the /etc/passwd file.	 If
      a match is found, the ~ and the matched login name are replaced by the
      login directory of the matched user.  This is called a tilde
      substitution.  If no match is found, the original text is left
      unchanged.  A ~, alone or before a /, is replaced by the value of the
      HOME parameter.  A ~ followed by a + or - is replaced by the value of
      the parameter PWD and OLDPWD, respectively.  In addition, tilde
      substitution is attempted when the value of a parameter assignment
      begins with a ~.

    Command Substitution
      The standard output from a command enclosed in parenthesis preceded by
      a dollar sign ($(command)) or a pair of back single quotes (accent
      grave) (`command`) can be used as part or all of a word; trailing
      new-lines are removed.  In the second (archaic) form, the string
      between the quotes is processed for special quoting characters before
      the command is executed (see Quoting below).  The command substitution
      $(cat file) can be replaced by the equivalent but faster $(<file).
      Command substitution of most special commands (built-ins) that do not
      perform I/O redirection are carried out without creating a separate
      process.	However, command substitution of a function creates a
      separate process to execute the function and all commands (built-in or
      otherwise) in that function.

      An arithmetic expression enclosed in double parenthesis preceded by a
      dollar sign ($((expression))) is replaced by the value of the
      arithmetic expression within the double parenthesis (see Arithmetic
      Evaluation below for a description of arithmetic expressions).



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 ksh(1)								      ksh(1)