Previous topic |
Next topic |
Contents |
Contact z/OS |
Library |
PDF
The for loop z/OS UNIX System Services User's Guide SA23-2279-00 |
|
The final control structure to be examined is the for loop.
It has the form:
The parameter name should be a variable name; if
this variable doesn't exist, it is created. The parameter list is
a list of strings separated by spaces. The shell begins by assigning
the first string in list to the variable name.
It then runs the commands once. Then the shell assigns the
next string in list to name, and repeats the commands. The shell runs the commands once for each string
in list.As a simple example of a shell script that uses for, consider:
When the shell looks at the for line, it expands
the expression *.c to produce a list containing
the names of all files (in the working directory) that have the suffix .c. The variable file is assigned each
of the names in this list, in turn. The result of the for loop
is to use the c89 command to compile all .c files
in the working directory. You could also write:
so that the shell script displayed each file name before
compiling it. This would let you keep track of what the script was
doing.As you can see, the for loop is a powerful control structure.
The list can also be created with command substitution, as
in:
Here the find command finds all .c files
in the working directory, and then compiles these files. This is similar
to the previous shell script, but it also looks at subdirectories
of the working directory. |
Copyright IBM Corporation 1990, 2014
|