HP-UX Reference (11i v2 04/09) - 1 User Commands A-M (vol 1)

k
ksh(1) ksh(1)
%number The job with the given number.
%string Any job whose command line begins with string.
%?string Any job whose command line contains string.
%% Current job.
%+ Equivalent to %%.
%- Previous job.
The shell learns immediately when a process changes state. It informs the user when a job is blocked and
prevented from further progress, but only just before it prints a prompt.
When the monitor mode is on, each background job that completes triggers any trap set for
CHLD.
Attempting to leave the shell while jobs are running or stopped produces the warning,
You have
stopped (running) jobs. Use the jobs command to identify them. An immediate attempt to
exit again terminates the stopped jobs; the shell does not produce a warning the second time.
Signals
The INT and QUIT signals for an invoked command are ignored if the command is followed by
& and the
monitor option is off. Otherwise, signals have the values inherited by the shell from its parent, with the
exception of signal 11 (but see also the
trap command below).
Execution
Substitutions are made each time a command is executed. If the command name matches one of the Spe-
cial Commands listed below, it is executed within the current shell process. Next,
ksh checks the com-
mand name to determine whether it matches one of the user-defined functions. If it does,
ksh saves the
positional parameters and then sets them to the arguments of the function call. The positional parameter
0 is set to the function name. When the function completes or issues a return, ksh
restores the posi-
tional parameter list and executes any trap set on
EXIT within the function. The value of a function is
the value of the last command executed. A function is executed in the current shell process. If a com-
mand name is not a special command or a user-defined function,
ksh creates a process and attempts
to execute the command using exec (see exec(2)).
The shell parameter
PATH defines the search path for the directory containing the command. Alternative
directory names are separated by a colon (:). The default path is /usr/bin: (specifying
/usr/bin
and the current directory in that order). Note that the current directory is specified by a null path name
which can appear immediately after the equals sign, between colon delimiters, or at the end of the path
list. The search path is not used if the command name contains a /. Otherwise, each directory in the
path is searched for an executable file. If the file has execute permissions but is not a directory or an exe-
cutable object code file, it is assumed to be a script file, which is a file of data for an interpreter. If the
first two characters of the script file are #!, exec (see exec(2)) expects an interpreter path name to fol-
low. exec then attempts to execute the specified interpreter as a separate process to read the entire
script file. If a call to exec fails, /usr/bin/ksh is spawned to interpret the script file. All non-
exported aliases, functions, and named parameters are removed in this case. If the shell command file
does not have read permission, or if the setuid and/or setgid bits are set on the file, the shell executes an
agent to set up the permissions and execute the shell with the shell command file passed down as an open
file. A parenthesized command is also executed in a sub-shell without removing non-exported quantities.
Command Re-entry
The text of the last
HISTSIZE (default 128) commands entered from a terminal device is saved in a his-
tory file. The file $HOME/.sh_history is used if the HISTFILE variable is not set or writable. A
shell can access the commands of all interactive shells that use the same named HISTFILE. The spe-
cial 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 com-
mand 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. The editor name - is used to skip the edit-
ing phase and to re-execute the command. In this case a substitution parameter of the form old=new can
be used to modify the command before execution. For example, if r is aliased to fc -e -, typing r
bad=good c re-executes the most recent command that starts with the letter c and replaces the first
occurrence of the string bad with the string good.
The history file will be trimmed when all of the following conditions occurs:
Its size is greater than four kilobytes.
HP-UX 11i Version 2: September 2004 − 11 − Hewlett-Packard Company Section 1−−431