ksh.1 (2010 09)

ManualsBrandsHP ManualsSoftwareHP-UX Manpages

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 argu-

ments, particularly the

set command.

Deﬁnitions

metacharacter

One of the following characters:

;&()|<>newline 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 com-

mand 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 preceded by a parameter assign-

ment 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 com-

mand 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 amper-

sand (&) 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 follow-

ing it to be executed only if the preceding pipeline returns a zero (nonzero) value. An arbitrary number of

newlines 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.

HP-UX 11i Version 3: September 2010 − 1 − Hewlett-Packard Company 1

Summary of content (26 pages)

PAGE 1
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.
PAGE 2
ksh(1) ksh(1) 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 ...
PAGE 3
ksh(1) ksh(1) 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.
PAGE 4
ksh(1) ksh(1) The shell supports a limited one-dimensional array facility. An element of an array parameter is referenced by a subscript. A subscript is denoted by a [ followed by an arithmetic expression (see Arithmetic Evaluation below) followed by a ]. To assign values to an array, use set -A name value ... . The value of all subscripts must be in the range of 0 through 1023. Arrays need not be declared.
PAGE 5
ksh(1) ksh(1) echo ${d:-$(pwd)} If the colon (:) is omitted from the above expressions, the shell only checks to determine whether or not parameter is set. The following parameters are set automatically by the shell: # The number of positional parameters in decimal. - Options supplied to the shell on invocation or by the set command. ? The decimal value returned by the last executed command. $ The process number of this shell.
PAGE 6
ksh(1) A kA ksh(1) FCEDIT The default editor name for the fc command. FPATH The search path for function definitions. This path is searched when a function with the -u attribute is referenced and when a command is not found. If an executable file is found, then it is read and executed in the current environment.
PAGE 7
ksh(1) ksh(1) retains explicit null arguments ( or ’ ’) but removes implicit null arguments (those resulting from parameters that have no values). File Name Generation Following substitution, each command word is processed as a pattern for file name expansion unless the -f option has been set. The form of the patterns is the Pattern Matching Notation defined by regexp (5). The word is replaced with sorted file names matching the pattern.
PAGE 8
ksh(1) ksh(1) Conditional Expressions. A conditional expression is used with the [[ compound command to test attributes of files and to compare strings. Word splitting and file name generation are not performed on the words between [[ and ]].
PAGE 9
ksh(1) ksh(1) otherwise, the file is truncated to zero length. Note that the noclobber test is only applied to regular files, not to named pipes or other file types. >|word Sames as >, except that it overrides the noclobber option. >>word Use file word as standard output. If the file exists, output is appended to it (by first searching for the end-of-file); otherwise, the file is created. <>word Open file word for reading and writing as standard input. If the file does not exist it is created.
PAGE 10
ksh(1) ksh(1) which must be noted in export or typeset -x commands. The environment for any simple-command or function can be augmented by prefixing it with one or more parameter assignments. A parameter assignment argument takes the form identifier =value. For example, TERM=450 cmd args and (export TERM; TERM=450; cmd args ) are equivalent (as far as the above execution of cmd is concerned except for special commands listed below that are preceded by a percent sign).
PAGE 11
ksh(1) ksh(1) is typed. A job run in the background stops if it tries to read from the terminal. Background jobs normally are allowed to produce output, but can be disabled by giving the stty tostop command. If the user sets this tty option, background jobs stop when trying to produce output. There are several ways to refer to jobs in the shell.
PAGE 12
ksh(1) ksh(1) The special command fc is used to list or edit a portion of this file. The portion of the file to be edited or listed can be selected by number or by giving the first character or characters of the command. A single command or range of commands can be specified. If no editor program is specified as an argument to fc, the value of the FCEDIT parameter is used. If FCEDIT is not defined, /usr/bin/ed is used. The edited command is printed and re-executed upon leaving the editor.
PAGE 13
ksh(1) ksh(1) specified, resume at the n-th enclosing loop. cd [ -L-P ] [ arg ] cd old new This command can take either of two forms. In the first form it changes the current directory to arg. If arg is - the directory is changed to the previous directory. The -L option (default) preserves logical naming when treating symbolic links. cd -L .. moves the current directory one path component closer to the root directory. The -P option preserves the physical path when treating symbolic links. cd -P ..
PAGE 14
ksh(1) ksh(1) getopts places the next option letter it finds inside variable name each time it is invoked with a + preceding it when arg begins with a +. The index of the next arg is stored in OPTIND. The option argument, if any, gets stored in OPTARG. A leading : in optstring causes getopts to store the letter of an invalid option in OPTARG, and to set name to ? for an unknown option and to : when a required option is missing. Otherwise, getopts prints an error message.
PAGE 15
ksh(1) ksh(1) subsequent assignment. % return [ n ] Causes a shell function to return to the invoking script with the return status specified by n. If n is omitted, the return status is that of the last command executed. Only the low 8 bits of n are passed back to the caller. If return is invoked while not in a function or executing a script by the . (dot) built-in command, it has the same effect as an exit command. set [ ±aefhkmnopstuvx | ±o option ] ... [ ±A name ] [ arg ...
PAGE 16
ksh(1) ksh(1) Print commands and their arguments as they are executed. Turns off -x and -v options and stops examining arguments for options. Do not change any of the options; useful in setting $1 to a value beginning with -. If no arguments follow this option, the positional parameters are unset. -x -- Using + instead of - before a option causes the option to be turned off. These options can also be used when invoking the shell. The current set of options can be examined by using $-.
PAGE 17
ksh(1) ksh(1) -i -l -r -t -u -x Parameter is an integer. This makes arithmetic faster. If n is nonzero, it defines the output arithmetic base; otherwise the first assignment determines the output base. Convert all uppercase characters to lowercase. The uppercase -u option is turned off. Any given name is marked "read only" and cannot be changed by subsequent assignment. Tag the named parameters. Tags are user definable and have no special meaning to the shell.
PAGE 18
ksh(1) ksh(1) even if name is an alias, a function, or a reserved word. Invoking ksh If the shell is invoked by exec (see exec (2)), and the first character of argument zero ($0) is -, the shell is assumed to be a login shell and commands are read first from /etc/profile. The expression ${HOME:-.}/.profile is then evaluated and an attempt to open the resulting filename is made. If the file is opened successfully, the file is read.
PAGE 19
ksh(1) ksh(1) The editing modes enable the user to look through a window at the current line. The default window width is 80, unless the value of COLUMNS is defined. If the line is longer than the window width minus two, a mark displayed at the end of the window notifies the user. The mark is a >, <, or * if the line extends respectively on the right, left, or both side(s) of the window. As the cursor moves and reaches the window boundaries, the window is centered about the cursor.
PAGE 20
ksh(1) A ksh(1) M-p Push the region from the cursor to the mark on the stack. kill (User-defined kill character, as defined by the stty (1) command, usually ˆG or @.) Kill the entire current line. If two kill characters are entered in succession, all subsequent consecutive kill characters cause a line feed (useful when using paper terminals). ˆY Restore last item removed from line (yank item back to the line). ˆL Line feed and print current line. @ (Null character) Set mark.
PAGE 21
ksh(1) ksh(1) command. In vi mode on most systems, canonical processing is initially enabled and the command is echoed again if the speed is 1200 baud or greater and contains any control characters, or if less than one second has elapsed since the prompt was printed. The ESC character terminates canonical processing for the remainder of the command and the user can then modify the command line. This scheme has the advantages of canonical processing with the type-ahead echoing of raw mode.
PAGE 22
ksh(1) ksh(1) [count]+ Equivalent to j. [count]G The command number count is fetched. The default is the first command in the history list. /string Search backward through history for a previous command containing string . string is terminated by a Return or Newline. If string is preceded by a ˆ, the matched line must begin with string . If string is null, the previous string is used. ?string Same as / but search in the forward direction.
PAGE 23
ksh(1) ksh(1) directory and a space is appended if the file is not a directory. Other Edit Commands [count]ymotion y[count]motion Yank current character through character that motion would move the cursor to and puts them into the delete buffer. The text and cursor are unchanged. Y Yanks from current position to end of line. Equivalent to y$. u Undo the last text modifying command. U Undo all the text modifying commands performed on the line.
PAGE 24
ksh(1) ksh(1) If you move the current directory or one above it, pwd may not give the correct response. Use the cd command with a full path name to correct this situation. Some very old shell scripts contain a caret (ˆ) as a synonym for the pipe character (|). Note however, ksh does not recognize the caret as a pipe character. If a command is piped into a shell command, all variables set in the shell command are lost when the command completes.
PAGE 25
ksh(1) ksh(1) environ(5), lang(5), regexp(5), signal(5).
PAGE 26
(Notes) A (Notes) kA 26 Hewlett-Packard Company −1− HP-UX 11i Version 3: September 2010