UNIX for OpenVMS Users, Third Edition
This book makes it easier to see what OpenVMS and UNIX have in common, and to take one s knowledge and experience in OpenVMS over to the brave new world of UNIX.
TABLE OF CONTENTS UNIX for OpenVMS Users, Third Edition
10.6: File Operators
10.6 File Operators
Table 10.5 lists C and Korn shell operators that test the characteristics of a file. Perl liberally borrows this syntax from both shells and adds a few operators of its own. There is no analog to these file operators in OpenVMS, although you can use values returned by the F$FILE_ATTRIBUTES lexical function to determine the attributes of an OpenVMS file. The features returned by F$FILE_ATTRIBUTES do not translate into UNIX file operators because of the different ways in which OpenVMS and UNIX treat files. An OpenVMS file is highly structured, and F$FILE_ATTRIBUTES returns information about that structure. A UNIX file is nothing more than a string of bytes. Since a UNIX file has no file structure information, file operators only return features like file ownership and permissions.
| C Shell Operator | Perl | Bash and Korn Shell Operator | OpenVMS Equivalent | UNIX Meaning |
|---|---|---|---|---|
| -a | [*] [ ] | True if object is any kind of file | ||
| -b | -b | True if file is a block-special file | ||
| -c | -c | True if file is a character special file | ||
| -d | -d | -d | True if file is a directory | |
| -e | -e | -e | [*] [ ] | True if file exists |
| -f | -f | -f | True if file is a regular file | |
| -T | True if file is "text" | |||
| -B | True if file is "binary" | |||
| -s | F$FILE_ATTRIBUTES (,"EOF") | If file exists and is not empty, returns size in... |
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