Shell commands changed for UNIX03

z/OS® UNIX is UNIX95 conformant, with extensions to commands using formats (such as uppercase option letters) to avoid conflicts with subsequent UNIX standards. The specification of new options and changed command behavior by SUSv3 (also known as UNIX03) has resulted in conflicts with IBM's extensions.

The _UNIX03 shell variable was introduced in z/OS 1.8 as a means of controlling whether certain shell commands behave according to Single UNIX Specifications, version 3 (SUSv3). _UNIX03=YES is only needed when an option or behavior conflicts with an existing z/OS implementation, and the SUSv3 behavior is desired. Additional command changes introduced in z/OS 1.9 have behavior conflicts controlled by the _UNIX03 variable. If _UNIX03 is not set (or set to "NO"), the z/OS 1.9 commands will maintain compatibility with prior releases.

Therefore, system programmers should make sure that _UNIX03 is not set in system-wide profiles (or setup scripts), including:

/etc/profile
/etc/csh.cshrc
/etc/csh.login
/etc/rc

Users who want the SUSv3 conformant behavior can set _UNIX03=YES in their own profile files, or in specific scripts or command invocations where it is needed.

Table 1 lists the commands that were changed for UNIX03. (It is not a complete list of changes to shell commands.) For more detail, see the specific command description.

Table 1. UNIX shell commands and _UNIX03
Command	z/OS release introduced	Affected option or behavior	_UNIX03 =YES	_UNIX03 is unset or not YES
awk	1.9	Stricter rules on a command-line argument being treated as a variable assignment Handling of break or continue statements outside of a loop	No effect Displays error and halts processing	No effect Displays warning, exits current pattern or function, and continues processing
bc	1.9	/usr/lib/lib.b improved cos() and sin() performance	No effect	No effect
cp	1.8	Options added or changed: -H \| L \| P -W seqparms	-P specifies symbolic link handling	-P params specifies sequential data set parameters
cksum	1.10	Output and diagnostic messages	Output defaults to space-separated: `cksum bytecount filename` If a filename operand is not specified, the path name and its leading white space is omitted. If a read error occurs, the checksum for that file is not displayed and a diagnostic message is sent to stderr.	Output defaults to tab-separated: `cksum bytecount filename` If a file operand is not specified, the path name and its leading tab is omitted. If a read error occurs, cksum attempts to display the available checksum to standard output and marks the output line with FSUM6199 [read error].
ed	1.9	Minor changes in subcommands c, i, g, G, v, V, l (lowercase L), s	c and i subcommands: accept address 0 as 1 g, G, v, V subcommands: unmark changed lines l (lowercase L) subcommand writes $ as \$ s subcommand: % without prior s subcommand is an error	c and i subcommands: reject address 0 g, G, v, V subcommands: leave lines marked l (lowercase L), subcommand does not escape $ characters s subcommand: % without prior s subcommand is accepted
file	1.9	Options added or changed: -d -M -i New magic file format -h handling of link to a nonexistent file	-m magic tested before /etc/magic magic file (byte, short, long) format are signed -h is the default Output separator char is a space	-m magic tested instead of /etc/magic magic file (byte, short, long) format are unsigned -h is not the default (The default is to follow symbolic links) Output separator char is a tab
mailx	1.9	Default command-mode subcommand Followup command-mode subcommand Honors the TZ environment variable Use tilde (~) as the escape character when escape variable is unset	Default subcommand is next Followup overrides the record variable	Default subcommand is print Followup does not override the record variable
od	1.9	Output of signed single-byte values	No effect	No effect
pax	1.8	Options added or changed: -H -x pax (new format) -o keyword=value (new keywords) pax -r restore of access permission bits, when neither -p p or -p e is specified	-o multiple keyword/value pairs must be separated by commas (with white space allowed before a keyword) Files are restored with permissions 0666 modified by umask.	-o multiple keyword/value pairs may be separated by commas or spaces Files are restored with saved permissions modified by umask.
sed	1.9	Subcommand preceded by ! s subcommand with w specified y subcommand with \n in a specified set of characters	One or more ! characters are allowed w and file must be separated by blanks \n is treated as a newline	Only one ! character is allowed wfile is allowed or may be separated by blanks \n is treated as a character ‘n’
sum	1.10	Output and diagnostic messages	Output defaults to space-separated: `checksum bytecount filename` If a filename operand is not specified, the path name and its leading white space is omitted. When a read error occurs, the checksum for that file is not displayed and a diagnostic message is sent to stderr.	Output defaults to tab-separated: `checksum bytecount filename` If a file operand is not specified, the path name and its leading tab is omitted. When a read error occurs, sum attempts to display the available checksum to stdout and marks the output line with FSUM6199 [read error].
tr	1.9	Option added: -C	-c complements the set of binary values in binary order	-c complements the set of characters in LC_COLLATE order (like the new -C behavior)
uudecode	1.9	Option added: -o outfile /dev/stdout	No effect	No effect
uuencode	1.9	Option added: -m /dev/stdout	No effect	No effect