z/OS V1R9.0 UNIX System Services Command ... - Christian Grothoff

Variables
*/*.[chyl]
Matches all .c, .h, .y, and .l files in a subdirectory of the working directory.
~mks/*.ksh
Matches all shell scripts in the home directory of user mks
(see “Directory Substitution” on page 559 for the use of ~).
If no files match the pattern, sh leaves the argument untouched. If the set option –f
or “–o noglob” is in effect, the shell does not perform filename generation.
Attention: Doublebyte characters in a filename may cause problems. For
instance, if you use a doublebyte character in which one of the bytes is a . (dot) or
/ (slash), the file system treats this as part of the pathname.
The shell maintains variables and can expand them where they are used in
command lines; see “Parameter Substitution” on page 559 for details.
A variable name must begin with an uppercase or lowercase letter or an underscore
(_). Subsequent characters in the name, if any, can be uppercase or lowercase
letters, underscores, or digits 0 through 9. You can assign a value to a variable with:
variable=value
For integer variables (see “Options” on page 717 for details), the value may be
specified as an arithmetic expression. For the syntax of an arithmetic expression,
see “Arithmetic Substitution” on page 562.
You can implicitly declare a variable as an array by using a subscript expression
when assigning a value, as in:
variable[arithmetic expression]=value
You can use a subscripted array variable anywhere that the shell allows an ordinary
variable. For the syntax of an arithmetic expression, see “Arithmetic Substitution” on
page 562. Also see typeset, export, and readonly for details about the attributes
of shell variables, and how shell variables can be exported to child processes.
For a list of variables that the shell either sets or understands, see “Shell Variables”
on page 569.
Shell Execution Environments
A shell execution environment is the set of conditions affecting most commands run
within the shell. It consists of:
v Open files
v The working directory (see cd)
v The file creation mask (see umask)
v The traps currently set (see trap)
v The shell parameters (see set and export)
v The shell functions currently defined (see “Command Execution” on page 556)
v Options (see set)
A child shell environmentstarts as a duplicate of the shell environment, except that
traps caught by the shell are set to default values in the child shell. Since the child
sh
Chapter 2. Shell command descriptions 567