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1. Commands and Utilities V4

Product Information

Environment Specification

Temporary Waivers

1.1 POSIX.2 Supported Features

Question 1: Which of the following options, specified in the <unistd.h> header, are available on the system?

Response

Macro Name	Meaning	Provided
_POSIX2_C_BIND	Implementation supports the C Language Binding option.	Yes   No
_POSIX2_C_DEV	Implementation supports the C Language Development Utilities option.	Yes   No
_POSIX2_CHAR_TERM	Implementation supports at least one terminal type.	Yes   No
_POSIX2_FORT_DEV	Implementation supports the FORTRAN Development Utilities option.	Yes   No
_POSIX2_FORT_RUN	Implementation supports the FORTRAN Run-time Utilities.	Yes   No
_POSIX2_LOCALEDEF	Implementation supports the creation of locales by the localedef utility.	Yes   No
_POSIX2_PBS	Implementation supports the Batch Environment Services and Utilities option.	Yes   No
_POSIX2_PBS_ACCOUNTING	Implementation supports the Batch Accounting option.	Yes   No
_POSIX2_PBS_CHECKPOINT	Implementation supports the Batch Checkpoint/Restart option.	Yes   No
_POSIX2_PBS_LOCATE	Implementation supports the Locate Batch Job Request option.	Yes   No
_POSIX2_PBS_MESSAGE	Implementation supports the Batch Job Message Request option.	Yes   No
_POSIX2_PBS_TRACK	Implementation supports the Track Batch Job Request option.	Yes   No
_POSIX2_SW_DEV	Implementation supports the Software Developments Utilities option.	Yes   No
_POSIX2_UPE	Implementation supports the User Portability Utilities option.	Yes   No

Rationale

For a Commands and Utilities V4 conformant implementation, _POSIX2_C_BIND, _POSIX2_CHAR_TERM, _POSIX2_LOCALEDEF, and _POSIX2_UPE must be supported. The other constants identify optional functionality that an implementation may or may not choose to support.

Reference

Technical Standard, Base Definitions, Issue 6, Chapter 13, Headers, <unistd.h>.

1.2 Development Utilities

1.2.1 Supported Commands

Question 2: Is the XSI Development Utilities option supported by this implementation?

Response

Yes   No

Rationale

The development utilities are required to exist on designated DEVELOPMENT systems but may not be present on all XSI-conformant systems.

Reference

Technical Standard, Base Definitions, Issue 6, Section 2.1.4.2, XSI Shell and Utilities Conformance.

1.3 FORTRAN Option

1.3.1 FORTRAN Utility

Question 3: Is the FORTRAN fort77 utility provided?

Response

Yes   No

Rationale

The fort77 utility is the command level interface to the FORTRAN compiler, which need not be provided.

Reference

Technical Standard, Base Definitions, Issue 6, Section 2.1.6.2, Shell and Utilities.

1.4 Specific Commands and Utilities

1.4.1 at

Question 4: How does the at command interpret a non-null SHELL environment variable?

Response

Uses the shell specified in the SHELL environment variable. Uses the login shell from the user database. Uses sh irrespective of the setting of SHELL.

Rationale

The interpretation of the SHELL environment variable can cause at to invoke different versions of the shell on some implementations.

Reference

Technical Standard, Shell and Utilities, Issue 6, Chapter 4, Utilities, at, ENVIRONMENT VARIABLES, SHELL.

1.4.2 awk

Question 5: What is the limit on the number of open streams provided by awk?

Response

open streams.

Rationale

The number of open streams that are available to awk may differ between implementations, possibly depending on the number of streams that are available to a process ({FOPEN_MAX}).

Reference

Technical Standard, Shell and Utilities, Issue 6, Chapter 4, Utilities, awk, Input/Output and General Functions, close().

1.4.3 batch

Question 6: How does the batch command interpret a non-null SHELL environment variable?

Response

Uses the shell specified in the SHELL environment variable. Uses the login shell from the user database. Uses sh irrespective of the setting of SHELL.

Rationale

The interpretation of the SHELL environment variable can cause batch to invoke different versions of the shell on some implementations.

Reference

Technical Standard, Shell and Utilities, Issue 6, Chapter 4, Utilities, batch, ENVIRONMENT VARIABLES, SHELL.

1.4.4 c99

Question 7: Which defined names are automatically provided by the compiler?

Response

The list of predefined macros follows. They can be printed (with their #define's values) with the command "c99 -W macros". _LP64 __AARCH64EL__ __AARCH64_CMODEL_SMALL__ __AARCH64_SIMD__ __APPLE_CC__ __APPLE__ __ARM64_ARCH_8__ __ARM_64BIT_STATE __ARM_ACLE __ARM_ALIGN_MAX_STACK_PWR __ARM_ARCH __ARM_ARCH_8_3__ __ARM_ARCH_8_4__ __ARM_ARCH_8_5__ __ARM_ARCH_ISA_A64 __ARM_ARCH_PROFILE __ARM_FEATURE_AES __ARM_FEATURE_ATOMICS __ARM_FEATURE_CLZ __ARM_FEATURE_COMPLEX __ARM_FEATURE_CRC32 __ARM_FEATURE_CRYPTO __ARM_FEATURE_DIRECTED_ROUNDING __ARM_FEATURE_DIV __ARM_FEATURE_DOTPROD __ARM_FEATURE_FMA __ARM_FEATURE_FP16_FML __ARM_FEATURE_FP16_SCALAR_ARITHMETIC __ARM_FEATURE_FP16_VECTOR_ARITHMETIC __ARM_FEATURE_FRINT __ARM_FEATURE_IDIV __ARM_FEATURE_JCVT __ARM_FEATURE_LDREX __ARM_FEATURE_NUMERIC_MAXMIN __ARM_FEATURE_QRDMX __ARM_FEATURE_SHA2 __ARM_FEATURE_SHA3 __ARM_FEATURE_SHA512 __ARM_FEATURE_SM3 __ARM_FEATURE_SM4 __ARM_FEATURE_UNALIGNED __ARM_FP __ARM_FP16_ARGS __ARM_FP16_FORMAT_IEEE __ARM_NEON __ARM_NEON_FP __ARM_NEON__ __ARM_PCS_AAPCS64 __ARM_SIZEOF_MINIMAL_ENUM __ARM_SIZEOF_WCHAR_T __ATOMIC_ACQUIRE __ATOMIC_ACQ_REL __ATOMIC_CONSUME __ATOMIC_RELAXED __ATOMIC_RELEASE __ATOMIC_SEQ_CST __BIGGEST_ALIGNMENT__ __BYTE_ORDER__ __CHAR16_TYPE__ __CHAR32_TYPE__ __CHAR_BIT__ __CLANG_ATOMIC_BOOL_LOCK_FREE __CLANG_ATOMIC_CHAR16_T_LOCK_FREE __CLANG_ATOMIC_CHAR32_T_LOCK_FREE __CLANG_ATOMIC_CHAR_LOCK_FREE __CLANG_ATOMIC_INT_LOCK_FREE __CLANG_ATOMIC_LLONG_LOCK_FREE __CLANG_ATOMIC_LONG_LOCK_FREE __CLANG_ATOMIC_POINTER_LOCK_FREE __CLANG_ATOMIC_SHORT_LOCK_FREE __CLANG_ATOMIC_WCHAR_T_LOCK_FREE __CONSTANT_CFSTRINGS__ __DBL_DECIMAL_DIG__ __DBL_DENORM_MIN__ __DBL_DIG__ __DBL_EPSILON__ __DBL_HAS_DENORM__ __DBL_HAS_INFINITY__ __DBL_HAS_QUIET_NAN__ __DBL_MANT_DIG__ __DBL_MAX_10_EXP__ __DBL_MAX_EXP__ __DBL_MAX__ __DBL_MIN_10_EXP__ __DBL_MIN_EXP__ __DBL_MIN__ __DECIMAL_DIG__ __DYNAMIC__ __ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__ __ENVIRONMENT_OS_VERSION_MIN_REQUIRED__ __FINITE_MATH_ONLY__ __FLT16_DECIMAL_DIG__ __FLT16_DENORM_MIN__ __FLT16_DIG__ __FLT16_EPSILON__ __FLT16_HAS_DENORM__ __FLT16_HAS_INFINITY__ __FLT16_HAS_QUIET_NAN__ __FLT16_MANT_DIG__ __FLT16_MAX_10_EXP__ __FLT16_MAX_EXP__ __FLT16_MAX__ __FLT16_MIN_10_EXP__ __FLT16_MIN_EXP__ __FLT16_MIN__ __FLT_DECIMAL_DIG__ __FLT_DENORM_MIN__ __FLT_DIG__ __FLT_EPSILON__ __FLT_EVAL_METHOD__ __FLT_HAS_DENORM__ __FLT_HAS_INFINITY__ __FLT_HAS_QUIET_NAN__ __FLT_MANT_DIG__ __FLT_MAX_10_EXP__ __FLT_MAX_EXP__ __FLT_MAX__ __FLT_MIN_10_EXP__ __FLT_MIN_EXP__ __FLT_MIN__ __FLT_RADIX__ __GCC_ATOMIC_BOOL_LOCK_FREE __GCC_ATOMIC_CHAR16_T_LOCK_FREE __GCC_ATOMIC_CHAR32_T_LOCK_FREE __GCC_ATOMIC_CHAR_LOCK_FREE __GCC_ATOMIC_INT_LOCK_FREE __GCC_ATOMIC_LLONG_LOCK_FREE __GCC_ATOMIC_LONG_LOCK_FREE __GCC_ATOMIC_POINTER_LOCK_FREE __GCC_ATOMIC_SHORT_LOCK_FREE __GCC_ATOMIC_TEST_AND_SET_TRUEVAL __GCC_ATOMIC_WCHAR_T_LOCK_FREE __GCC_HAVE_DWARF2_CFI_ASM __GCC_HAVE_SYNC_COMPARE_AND_SWAP_1 __GCC_HAVE_SYNC_COMPARE_AND_SWAP_2 __GCC_HAVE_SYNC_COMPARE_AND_SWAP_4 __GCC_HAVE_SYNC_COMPARE_AND_SWAP_8 __GNUC_MINOR__ __GNUC_PATCHLEVEL__ __GNUC_STDC_INLINE__ __GNUC__ __GXX_ABI_VERSION __INT16_C_SUFFIX__ __INT16_FMTd__ __INT16_FMTi__ __INT16_MAX__ __INT16_TYPE__ __INT32_C_SUFFIX__ __INT32_FMTd__ __INT32_FMTi__ __INT32_MAX__ __INT32_TYPE__ __INT64_C_SUFFIX__ __INT64_FMTd__ __INT64_FMTi__ __INT64_MAX__ __INT64_TYPE__ __INT8_C_SUFFIX__ __INT8_FMTd__ __INT8_FMTi__ __INT8_MAX__ __INT8_TYPE__ __INTMAX_C_SUFFIX__ __INTMAX_FMTd__ __INTMAX_FMTi__ __INTMAX_MAX__ __INTMAX_TYPE__ __INTMAX_WIDTH__ __INTPTR_FMTd__ __INTPTR_FMTi__ __INTPTR_MAX__ __INTPTR_TYPE__ __INTPTR_WIDTH__ __INT_FAST16_FMTd__ __INT_FAST16_FMTi__ __INT_FAST16_MAX__ __INT_FAST16_TYPE__ __INT_FAST32_FMTd__ __INT_FAST32_FMTi__ __INT_FAST32_MAX__ __INT_FAST32_TYPE__ __INT_FAST64_FMTd__ __INT_FAST64_FMTi__ __INT_FAST64_MAX__ __INT_FAST64_TYPE__ __INT_FAST8_FMTd__ __INT_FAST8_FMTi__ __INT_FAST8_MAX__ __INT_FAST8_TYPE__ __INT_LEAST16_FMTd__ __INT_LEAST16_FMTi__ __INT_LEAST16_MAX__ __INT_LEAST16_TYPE__ __INT_LEAST32_FMTd__ __INT_LEAST32_FMTi__ __INT_LEAST32_MAX__ __INT_LEAST32_TYPE__ __INT_LEAST64_FMTd__ __INT_LEAST64_FMTi__ __INT_LEAST64_MAX__ __INT_LEAST64_TYPE__ __INT_LEAST8_FMTd__ __INT_LEAST8_FMTi__ __INT_LEAST8_MAX__ __INT_LEAST8_TYPE__ __INT_MAX__ __LDBL_DECIMAL_DIG__ __LDBL_DENORM_MIN__ __LDBL_DIG__ __LDBL_EPSILON__ __LDBL_HAS_DENORM__ __LDBL_HAS_INFINITY__ __LDBL_HAS_QUIET_NAN__ __LDBL_MANT_DIG__ __LDBL_MAX_10_EXP__ __LDBL_MAX_EXP__ __LDBL_MAX__ __LDBL_MIN_10_EXP__ __LDBL_MIN_EXP__ __LDBL_MIN__ __LITTLE_ENDIAN__ __LONG_LONG_MAX__ __LONG_MAX__ __LP64__ __MACH__ __NO_INLINE__ __OBJC_BOOL_IS_BOOL __OPENCL_MEMORY_SCOPE_ALL_SVM_DEVICES __OPENCL_MEMORY_SCOPE_DEVICE __OPENCL_MEMORY_SCOPE_SUB_GROUP __OPENCL_MEMORY_SCOPE_WORK_GROUP __OPENCL_MEMORY_SCOPE_WORK_ITEM __ORDER_BIG_ENDIAN__ __ORDER_LITTLE_ENDIAN__ __ORDER_PDP_ENDIAN__ __PIC__ __POINTER_WIDTH__ __PRAGMA_REDEFINE_EXTNAME __PTRDIFF_FMTd__ __PTRDIFF_FMTi__ __PTRDIFF_MAX__ __PTRDIFF_TYPE__ __PTRDIFF_WIDTH__ __REGISTER_PREFIX__ __SCHAR_MAX__ __SHRT_MAX__ __SIG_ATOMIC_MAX__ __SIG_ATOMIC_WIDTH__ __SIZEOF_DOUBLE__ __SIZEOF_FLOAT__ __SIZEOF_INT128__ __SIZEOF_INT__ __SIZEOF_LONG_DOUBLE__ __SIZEOF_LONG_LONG__ __SIZEOF_LONG__ __SIZEOF_POINTER__ __SIZEOF_PTRDIFF_T__ __SIZEOF_SHORT__ __SIZEOF_SIZE_T__ __SIZEOF_WCHAR_T__ __SIZEOF_WINT_T__ __SIZE_FMTX__ __SIZE_FMTo__ __SIZE_FMTu__ __SIZE_FMTx__ __SIZE_MAX__ __SIZE_TYPE__ __SIZE_WIDTH__ __SSP__ __STDC_HOSTED__ __STDC_NO_THREADS__ __STDC_UTF_16__ __STDC_UTF_32__ __STDC_VERSION__ __STDC__ __STRICT_ANSI__ __UINT16_C_SUFFIX__ __UINT16_FMTX__ __UINT16_FMTo__ __UINT16_FMTu__ __UINT16_FMTx__ __UINT16_MAX__ __UINT16_TYPE__ __UINT32_C_SUFFIX__ __UINT32_FMTX__ __UINT32_FMTo__ __UINT32_FMTu__ __UINT32_FMTx__ __UINT32_MAX__ __UINT32_TYPE__ __UINT64_C_SUFFIX__ __UINT64_FMTX__ __UINT64_FMTo__ __UINT64_FMTu__ __UINT64_FMTx__ __UINT64_MAX__ __UINT64_TYPE__ __UINT8_C_SUFFIX__ __UINT8_FMTX__ __UINT8_FMTo__ __UINT8_FMTu__ __UINT8_FMTx__ __UINT8_MAX__ __UINT8_TYPE__ __UINTMAX_C_SUFFIX__ __UINTMAX_FMTX__ __UINTMAX_FMTo__ __UINTMAX_FMTu__ __UINTMAX_FMTx__ __UINTMAX_MAX__ __UINTMAX_TYPE__ __UINTMAX_WIDTH__ __UINTPTR_FMTX__ __UINTPTR_FMTo__ __UINTPTR_FMTu__ __UINTPTR_FMTx__ __UINTPTR_MAX__ __UINTPTR_TYPE__ __UINTPTR_WIDTH__ __UINT_FAST16_FMTX__ __UINT_FAST16_FMTo__ __UINT_FAST16_FMTu__ __UINT_FAST16_FMTx__ __UINT_FAST16_MAX__ __UINT_FAST16_TYPE__ __UINT_FAST32_FMTX__ __UINT_FAST32_FMTo__ __UINT_FAST32_FMTu__ __UINT_FAST32_FMTx__ __UINT_FAST32_MAX__ __UINT_FAST32_TYPE__ __UINT_FAST64_FMTX__ __UINT_FAST64_FMTo__ __UINT_FAST64_FMTu__ __UINT_FAST64_FMTx__ __UINT_FAST64_MAX__ __UINT_FAST64_TYPE__ __UINT_FAST8_FMTX__ __UINT_FAST8_FMTo__ __UINT_FAST8_FMTu__ __UINT_FAST8_FMTx__ __UINT_FAST8_MAX__ __UINT_FAST8_TYPE__ __UINT_LEAST16_FMTX__ __UINT_LEAST16_FMTo__ __UINT_LEAST16_FMTu__ __UINT_LEAST16_FMTx__ __UINT_LEAST16_MAX__ __UINT_LEAST16_TYPE__ __UINT_LEAST32_FMTX__ __UINT_LEAST32_FMTo__ __UINT_LEAST32_FMTu__ __UINT_LEAST32_FMTx__ __UINT_LEAST32_MAX__ __UINT_LEAST32_TYPE__ __UINT_LEAST64_FMTX__ __UINT_LEAST64_FMTo__ __UINT_LEAST64_FMTu__ __UINT_LEAST64_FMTx__ __UINT_LEAST64_MAX__ __UINT_LEAST64_TYPE__ __UINT_LEAST8_FMTX__ __UINT_LEAST8_FMTo__ __UINT_LEAST8_FMTu__ __UINT_LEAST8_FMTx__ __UINT_LEAST8_MAX__ __UINT_LEAST8_TYPE__ __USER_LABEL_PREFIX__ __VERSION__ __WCHAR_MAX__ __WCHAR_TYPE__ __WCHAR_WIDTH__ __WINT_MAX__ __WINT_TYPE__ __WINT_WIDTH__ __aarch64__ __apple_build_version__ __arm64 __arm64__ __clang__ __clang_literal_encoding__ __clang_major__ __clang_minor__ __clang_patchlevel__ __clang_version__ __clang_wide_literal_encoding__ __llvm__ __nonnull __null_unspecified __nullable __pic__ __strong __unsafe_unretained __weak

Rationale

The automatic provision of defined names by the compiler can cause these names to be unavailable in the name space for defined names.

Reference

Technical Standard, Shell and Utilities, Issue 6, Chapter 4, Utilities, c99, OPTIONS, -D.

Question 8: When multiple input files are specified, where does c99 direct identification messages designating the start of each input file processing?

Response

Standard output. Standard error. These messages are not generated.

Rationale

These messages, if produced, must be written to one or the other of standard output and standard error, but not to both. The destination of these messages is useful in determining redirections that are necessary to identify the input files from which warning messages are generated.

Reference

Technical Standard, Shell and Utilities, Issue 6, Chapter 4, Utilities, c99, STDOUT and STDERR.

Question 9: What are the limits associated with external symbols imposed by c99?

Response

Description	Minimum Maximum	Implementation Maximum
Number of significant bytes	31
Number of external symbols per source or object file	511
Total number of external symbols	4095

Rationale

These limits vary between implementations and cannot be reset by the user. The XCU definition gives the minimum maximum value for each of the values. Some applications may require larger limits than these minimum maxima.

Reference

Technical Standard, Shell and Utilities, Issue 6, Chapter 4, Utilities, c99, EXTENDED DESCRIPTION, External Symbols.

1.4.5 chown

Question 10: Does the implementation support user and group IDs for symbolic links?

Response

Yes   No

Rationale

The behavior of a conforming implementation in this area is not mandated in the specification and needs to be defined.

Reference

Technical Standard, Shell and Utilities, Issue 6, Chapter 4, Utilities, chown.

1.4.6 cp

Question 11: What is the affect of alternate access control mechanisms on file copies?

Response

If a file has associated Access Control Lists (ACLs), they will be preserved when using the -p option.

Rationale

Because of the additional restrictions on creating files and reading data from files, the cp utility may not behave as described when alternate access control mechanisms are in use.

Reference

Technical Standard, Shell and Utilities, Issue 6, Chapter 4, Utilities, cp, DESCRIPTION (final paragraph).

1.4.7 date

Question 12: Does date permit the setting of the date and time?

Response

Yes   No

Rationale

Some systems, particularly those that are hosted as part of a total system environment, do not allow the date command to set the date. On such systems, the setting of the date can only be accomplished from the host environment.

Reference

Technical Standard, Shell and Utilities, Issue 6, Chapter 4, Utilities, date, OPERANDS, mmddhhmm[yy].

1.4.8 ex

Question 13: What restrictions are imposed on the set of commands within the rhs of the map command?

Response

None

Rationale

Implementations may impose restrictions on the commands that can be used by macros in visual mode.

Reference

Technical Standard, Shell and Utilities, Issue 6, Chapter 4, Utilities, ex, EXTENDED DESCRIPTION, Command Descriptions in ex, Map.

1.4.9 fc

Question 15: Is the history list mechanism disabled for users with appropriate privileges who do not set HISTFILE?

Response

Yes   No

Rationale

The specification states that an implementation may, in certain circumstances, disable the history list mechanism for users with appropriate privileges who do not set HISTFILE. This could have some security implications.

Reference

Technical Standard, Shell and Utilities, Issue 6, Chapter 4, Utilities, fc, ENVIRONMENT VARIABLES, HISTFILE.

1.4.10 fort77

Question 15: When multiple input files are specified, where does fort77 direct identification messages designating the start of each input file processing?

Response

Standard output. Standard error. These messages are not generated. Not applicable.

Rationale

These messages, if produced, must be written to one or the other of standard output and standard error, but not to both. The destination of these messages is useful in determining redirections that are necessary to identify the input files from which warning messages are generated. If the response is not applicable then the fort77 utility is not supported.

Reference

Technical Standard, Shell and Utilities, Issue 6, Chapter 4, Utilities, fort77, STDERR.

Question 16: What are the limits associated with external symbols imposed by fort77?

Response

Description	Minimum Maximum	Implementation Maximum
Number of significant bytes	31
Number of external symbols per source or object file	511
Total number of external symbols	4095

Rationale

These limits vary between implementations and cannot be reset by the user. The specification gives the minimum maximum value for each of the values. Some applications may require larger limits than these minimum maxima. If the responses are not supported then the fort77 utility is not supported.

Reference

Technical Standard, Shell and Utilities, Issue 6, Chapter 4, Utilities, fort77, EXTENDED DESCRIPTION, External Symbols.

1.4.11 lex

Question 17: Where are error messages sent when the lex -t option is not specified?

Response

Standard output. Standard error. Not applicable.

Rationale

These messages can be directed to either standard output or standard error, though the messages are not allowed to be directed to both. An application may wish to redirect these messages to a file.

Reference

Technical Standard, Shell and Utilities, Issue 6, Chapter 4, Utilities, lex, STDOUT.

1.4.12 ln

Question 18: Can ln create links to a directory?

Response

Yes   No

Rationale

Implementations may disallow the creation of hard links to a directory, even though the executing process has the appropriate privileges.

Reference

Technical Standard, Shell and Utilities, Issue 6, Chapter 4, Utilities, ln, OPERANDS, source_file.

1.4.13 localedef

Question 19: What is the default character mapping used when the localedef -f option is not specified?

Response

ISO_646.irv:1991

Rationale

The specification does not define a specific character mapping as the default for conforming systems. This character mapping provides encoding information for the members of the portable character set.

Reference

Technical Standard, Shell and Utilities, Issue 6, Chapter 4, Utilities, localedef, OPTIONS, -f.

1.4.15 lp

Question 20: What lp option or operator command is used to suppress the printing of a banner page?

Response

None

Rationale

The user may require that banner pages are suppressed in cases where pre-printed forms are used and the stationary is of a non-standard length.

Reference

Technical Standard, Shell and Utilities, Issue 6, Chapter 4, Utilities, lp, DESCRIPTION.

1.4.15 ls

Question 21: How many bytes are in a block as reported by ls?

Response

Rationale

The block size used by ls to report the number of blocks occupied by a file varies from system to system; often this depends on the underlying file system architecture.

Reference

Technical Standard, Shell and Utilities, Issue 6, Chapter 4, Utilities, ls, OPTIONS, -s.

1.4.16 make

Question 22: What additional variables does make add to its environment?

Response

MAKEFLAGS, MFLAGS, MAKELEVEL=1

Rationale

The implementation of make may set certain environment variables on invocation of make. These variables may not be set by the user, thus reducing the name space for environment variables.

Reference

Technical Standard, Shell and Utilities, Issue 6, Chapter 4, Utilities, make, EXTENDED DESCRIPTION, Makefile Execution.

Question 23: Does the default MAKEFLAGS environment variable contain additional implementation-defined options?

Response

None

Rationale

The implementation of make may set certain default MAKEFLAGS options on invocation of make. These variables are in addition to those set by the user on the command line and could affect the processing of make.

Reference

Technical Standard, Shell and Utilities, Issue 6, Chapter 4, Utilities, make, EXTENDED DESCRIPTION, Makefile Execution.

1.4.17 newgrp

Question 24: Does newgrp allow users who are not listed as a member of a group which has no password to change to that group?

Response

Yes   No

Rationale

On some implementations, a user who is not listed as a member of a group may change to that group in the case that there is no password associated with the group.

Reference

Technical Standard, Shell and Utilities, Issue 6, Chapter 4, Utilities, newgrp, DESCRIPTION.

Question 25: Are there any other implementation-defined authorization restrictions that affect newgrp?

Response

None

Rationale

Some implementations may impose accounting or other restrictions that could cause newgrp to deny activity to a group member. For example, a resource quota system could be implemented on a group basis that would limit the ability to join a group until the resources were available to the group.

Reference

Technical Standard, Shell and Utilities, Issue 6, Chapter 4, Utilities, newgrp, DESCRIPTION.

1.4.18 nice and renice

Question 26: What are the limits and default values used by nice and renice?

Response

Maximum nice value
Minimum nice value
Default nice value

Rationale

Each of these values differs between implementations and the range of values gives the user some control over the relative priority of processes.

Reference

Technical Standard, Shell and Utilities, Issue 6, Chapter 4, Utilities, nice, DESCRIPTION.

1.4.19 pax

Question 27: What is the default archive format used by pax?

Response

ustar

Rationale

The implementation has a choice in which format to use when creating archives. When it is reading an archive created in any format that it understands, the pax utility will read the archive in the format as written.

Reference

Technical Standard, Shell and Utilities, Issue 6, Chapter 4, Utilities, pax, DESCRIPTION.

Question 28: How does pax handle reading and writing of archives that span multiple files?

Response

pax will prompt for the pathname of the file or device of the next volume in the archive

Rationale

In many cases pax will take actions, such as prompting the user for the device name to use for the next archive file, when the current archive file is full. There may be extensions to the syntax of pax which allow the user to specify the address to use to access subsequent files.

Reference

Technical Standard, Shell and Utilities, Issue 6, Chapter 4, Utilities, pax, DESCRIPTION.

Question 29: How does pax handle invalid filenames when it is extracting files from an archive?

Response

A diagnostic message is written to standard error and a non-zero exit status will be returned, but processing will continue

Rationale

An implementation may either extract the data associated with these files into files named in an implementation-defined manner or may issue an error indicating that the file is being ignored. If pax extracts the file, it is necessary for the user either to be informed of the file that is used or to know the algorithm that pax uses in generating these filenames.

Reference

Technical Standard, Shell and Utilities, Issue 6, Chapter 4, Utilities, pax, EXTENDED DESCRIPTION, The cpio Filename.

1.4.20 printf

Question 30: Does printf support the e, E, f, g, and G floating point conversion specifications?

Response

Yes   No

Rationale

The support of these conversions is optional.

Reference

Technical Standard, Shell and Utilities, Issue 6, Chapter 4, Utilities, printf, EXAMPLES.

1.4.21 sh

Question 31: Is the environment variable IFS ignored when the shell is invoked?

Response

Yes   No

Rationale

The specification allows the sh command ignore the setting of the IFS environment variable on invocation. The setting of this variable has been used to breach security on systems which use the shell to interpret a call to the system() and execvp() interfaces.

Reference

Technical Standard, Shell and Utilities, Issue 6, Chapter 4, Utilities, sh, ENVIRONMENT VARIABLES, IFS.

1.4.22 touch

Question 32: What is the latest date after the Epoch that can be used by touch?

Response

Rationale

Because of the limitations on the storage of times in the stat structure associated with a file, there is a limitation on the valid dates that can be specified to touch. This is directly related to the value that can be stored in the integer or real-floating type time_t.

Reference

Technical Standard, Shell and Utilities, Issue 6, Chapter 4, Utilities, touch, OPTIONS, -t.

1.4.23 yacc

Question 33: What are the limits of yacc's internal tables?

Response

Description	Minimum Maximum	Implementation Maximum
Number of tokens	126
Number of non-terminals	200
Number of rules	300
Number of states	600
Length of rules	5200
Number of actions	4000

Rationale

These internal table sizes vary between implementations and cannot be reset by the user. The specification gives the minimum maximum value for each of the table values.

Reference

Technical Standard, Shell and Utilities, Issue 6, Chapter 4, Utilities, yacc, EXTENDED DESCRIPTION, Limits.

1.5 C-language Programming Environments

1.5.1 Supported Environments

Question 34: What C-language programming environments are provided?

Response

Programming Environment	Provided
The implementation provides a C-language programming environment with 32-bit int, long, pointer and off_t types.	Yes   No
The implementation provides a C-language programming environment with 32-bit int, long and pointer types and an off_t type using at least 64 bits.	Yes   No
The implementation provides a C-language programming environment with 32-bit int, and 64-bit long, pointer and off_t types.	Yes   No
The implementation provides a C-language programming environment with int using at least 32-bits, and long, pointer and off_t types using at least 64 bits.	Yes   No

Rationale

Shell and Utilities, Issue 6 defines these scenarios as possible C-language programming environment offerings.

Reference

Technical Standard, Shell and Utilities, Issue 6, Chapter 4, Utilities, c99,

1.5.2 Default Environment

Question 35: What C-language programming environment is the default?

Response

Programming Environment	Provided
The implementation's default C-language programming environment provides 32-bit int, long, pointer and off_t types.	Yes   No
The implementation's default C-language programming environment provides 32-bit int, long and pointer types and an off_t type using at least 64 bits.	Yes   No
The implementation's default C-language programming environment provides 32-bit int, and 64-bit long, pointer and off_t types.	Yes   No
The implementation's default C-language programming environment provides int using at least 32-bits, and long, pointer and off_t types using at least 64 bits.	Yes   No

Rationale

Shell and Utilities, Issue 6 specifies that the default must be one of the above. Note that the third choice overlaps with the fourth choice.

Reference

Technical Standard, Shell and Utilities, Issue 6, Chapter 4, Utilities, c99,

1.6 Batch Environment Services Option

1.6.1 Batch Job Attributes

Question 36: Does qalter attempt to alter the attributes of a batch job in the RUNNING state?

Response

Yes. No. Not applicable.

Rationale

The specification states that an attempt to alter the attributes of a batch job in the RUNNING state is implementation-defined.

Reference

Technical Standard, Shell and Utilities, Issue 6, Chapter 4, Utilities, qalter

1.6.2 Batch Job Hold Types

Question 37: Does the implementation define other hold types for the qalter , qhold, qrls and qselect utilities?

Response

Yes. No. Not applicable.

Rationale

The specification states that an implementation may define other keep types for these utilities and that the conformance document shall describe any additional keep types, how they are specified, their internal behavior, and how they affect the behavior of the utility.

Reference

Technical Standard, Shell and Utilities, Issue 6, Chapter 4, Utilities, qalter, qhold, qrls and qselect.

1.6.3 Batch Job Join Types

Question 38: Does the implementation define other join types for the qalter and qsub utilities ?

Response

Yes. No. Not applicable.

Rationale

The specification states that an implementation may define other keep types for these utilities and that the conformance document shall describe any additional keep types, how they are specified, their internal behavior, and how they affect the behavior of the utility.

Reference

Technical Standard, Shell and Utilities, Issue 6, Chapter 4, Utilities, qalter and qsub.

1.6.4 Batch Job Keep Types

Question 39: Does the implementation define other keep types for the qalter and qsub utilities?

Response

Yes. No. Not applicable.

Rationale

The specification states that an implementation may define other keep types for these utilities and that the conformance document shall describe any additional keep types, how they are specified, their internal behavior, and how they affect the behavior of the utility.

Reference

Technical Standard, Shell and Utilities, Issue 6, Chapter 4, Utilities, qalter and qsub.

1.6.5 Batch Job Mail Types

Question 40: Does the implementation define other mail types for the qalter and qsub utilties?

Response

Yes. No. Not applicable.

Rationale

The specification states that an implementation may define other keep types for these utilities and that the conformance document shall describe any additional keep types, how they are specified, their internal behavior, and how they affect the behavior of the utility.

Reference

Technical Standard, Shell and Utilities, Issue 6, Chapter 4, Utilities, qalter and qsub.

1.6.6 Mail Address Interpretation

Question 41: How do the qalter and qsub utilities interpret the mail_address argument to the -M option?

Response

Not applicable

Rationale

The specification states that the interpretation of mail_address is implementation-defined.

Reference

Technical Standard, Shell and Utilities, Issue 6, Chapter 4, Utilities, qalter and qsub.

1.6.7 Locating a Batch Job on Other Servers

Question 42: Does the qalter utility attempt to locate a batch job on other servers?

Response

Yes. No. Not applicable.

Rationale

The specification states that whether or not the qalter utility attempts to locate the batch job on other batch servers is implementation-defined.

Reference

Technical Standard, Shell and Utilities, Issue 6, Chapter 4, Utilities, qalter.

1.6.8 Output of Diagnostic Messages

Question 43: Do the qdel,qhold,qmove,qmsg,qrerun,qrls,qsig and qstat utilities wait to output a diagnostic message while attempting to locate a job on other servers?

Response

Utility Name	Output a Diagnostic?
qdel	Yes. No. Not applicable.
qhold	Yes. No. Not applicable.
qmove	Yes. No. Not applicable.
qmsg	Yes. No. Not applicable.
qrerun	Yes. No. Not applicable.
qrls	Yes. No. Not applicable.
qsig	Yes. No. Not applicable.
qstat	Yes. No. Not applicable.

Rationale

The specification states that whether or not these utilities wait to output the diagnostic message while attempting to locate the job on other servers is implementation-defined.

Reference

Technical Standard, Shell and Utilities, Issue 6, Chapter 4, Utilities, qdel,qhold,qmove,qmsg,qrerun,qrls,qsig and qstat.

1.6.9 Implementation-defined File for qmsg

Question 44: What is the name and location of the implementation-defined file that the qmsg utility writes the message to if neither -O nor the -E options are specified?

Response

Not applicable

Rationale

The specification states that if neither the -O nor the -E option is presented to the qmsg utility, the utility shall write the message into an implementation-defined file and that the conformance document shall describe the name and location of the implementation-defined file.

Reference

Technical Standard, Shell and Utilities, Issue 6, Chapter 4, Utilities, qmsg.

1.6.10 Matching Job_Name Attribute For qselect

Question 45: What is the format that the qselect utility supports for matching against the Job_Name attribute for the -N option?

Response

Not applicable

Rationale

The specification states that an implementation shall describe in the conformance document the format it supports for matching against the Job_Name attribute.

Reference

Technical Standard, Shell and Utilities, Issue 6, Chapter 4, Utilities, qselect.

1.6.11 Default Batch Server For qselect

Question 46: How does the qselect utility determine the default batch server?

Response

Not applicable

Rationale

The specification states that if the option-argument describes only a batch queue, the qselect utility shall select only batch jobs from the batch queue of the specified name at the default batch server. The means by which qselect determines the default server is implementation-defined.

Reference

Technical Standard, Shell and Utilities, Issue 6, Chapter 4, Utilities, qselect.

1.6.12 Implementation-defined Information for the -f option to qstat

Question 47: What additional implementation-defined information, if any, about the batch job or batch queue are displayed for the -f option to the qstat utility?

Response

Not applicable

Rationale

The specification states that the additional contents and format of a full display are implementation-defined.

Reference

Technical Standard, Shell and Utilities, Issue 6, Chapter 4, Utilities, qstat.

1.6.13 Priority Attribute For -p Option To qsub

Question 48: What is the value of the Priority attribute if the -p option is not presented to the qsub utility?

Response

Not applicable

Rationale

The specification states that if the -p option is not presented to the qsub utility, the value of the Priority attribute is implementation-defined.

Reference

Technical Standard, Shell and Utilities, Issue 6, Chapter 4, Utilities, qsub.

1.6.15 Default Destination for qsub

Question 49: What is the default destination if the -q option is not presented to the qsub utility?

Response

Not applicable

Rationale

The specification states that if the -q option is not presented to the qsub utility, the qsub utility shall submit the batch job to the default destination. The mechanism for determining the default destination is implementation-defined.

Reference

Technical Standard, Shell and Utilities, Issue 6, Chapter 4, Utilities, qsub.

1.6.15 Default Shell for qsub

Question 50: What is the mechanism for setting and determining the value of the default shell for the qsub utility?

Response

Not applicable

Rationale

The specification states that the conformance document shall describe the mechanism used to set the default shell and determine the current value of the default shell. An implementation shall provide a means for the installation to set the default shell to the login shell of the user under which the batch job is to execute.

Reference

Technical Standard, Shell and Utilities, Issue 6, Chapter 4, Utilities, qsub.

1.6.16 Shell Script Format for qsub

Question 51: What is the format of shell commments recognized by the qsub utility for the script file argument?

Response

Not applicable

Rationale

The specification states that the qsub utility shall continue to process a directive prefix line until after a is encountered. An implementation may ignore lines which, according to the syntax of the shell that will interpret the script, are comments. An implementation shall describe in the conformance document the format of any shell comments that it will recognize.

Reference

Technical Standard, Shell and Utilities, Issue 6, Chapter 4, Utilities, qsub.

2. Appendix

Testing Environment Addendum:
1. macOS version 15.0 Sequoia, like previous versions, includes an additional security mechanism known as System Integrity Protection (SIP).  This security policy applies to every running process, including privileged code and code that runs out of the sandbox. The policy extends additional protections to components on disk and at run-time, only allowing system binaries to be modified by the system installer and software updates. Code injection and runtime attachments to system binaries are no longer permitted.

To run the VSC conformance test suite on an Apple Silicon Mac we first disable SIP as follows:

	-	Shut down the system.
	-	Press and hold the power button. Keep holding it while you see the Apple logo and the message "Continue holding for startup options"
	-	Release the power button when you see "Loading startup options"
	-	Choose "Options" and click "Continue"
	-	Select an administrator account and enter its password.
	-	From the Utilities menu in the Menu Bar, select Terminal.
	-	At the prompt, issue the following command: "csrutil disable"
	-	You should see a message that SIP is disabled. From the Apple menu, select "Restart".

2. By default, the APFS file system updates a file's atime lazily. To run the Conformance Test Suites, or more generally to get UNIX Standard atime behavior, mount the test partitions (including /System/Volumes/Data) with the "strictatime" option:

    mount -o strictatime <specialfilename> <mountpoint>

3. APFS file systems can be formatted as either case-sensitive or case-insensitive. Always format as case-sensitive for UNIX Conformant behavior.

4. macOS has a file indexing service, Spotlight, that runs in the background and may affect file access times. For UNIX Conformance Testing we disable Spotlight. You can do that with this command:

    sudo launchctl unload -w /System/Library/LaunchDaemons/com.apple.metadata.mds.plist

Spotlight can be re-enabled with

    sudo launchctl load -w /System/Library/LaunchDaemons/com.apple.metadata.mds.plist

5. By default, macOS coalesces timeouts that are scheduled to occur within 5 seconds of each other. This can randomly cause some "at" tests to occasionally fail so we disable this coalescing when testing. To disable timeout coalescing issue this command:

    sudo sysctl -w kern.timer.coalescing_enabled=0

6. By default there is no root user. We enable the root user for testing using the following series of steps:
	-	Launch the Directory Utility by pressing Command and Space, and then typing "Directory Utility"
	-	Click the Lock icon in Directory Utility and authenticate by entering an Administrator username and password.
	-	From the Menu Bar in Directory Utility:
	-	Choose Edit ->  Enable Root User. Then enter a password for the root user, and confirm it.
	-	Note: If you choose, you can later Disable Root User via the same menu.

7. In macOS Sequoia the root volume is authenticated and immutable. Because of this, and because of the way that you have to configure uucp, you should take the following steps before using uucp (and we do these before running the uu* tests):

    - Copy the following binaries from /usr/bin to /usr/local/bin
        uucp
        uuname
        uustat
        uux
    - Copy the following binaries from /usr/sbin to /usr/local/bin:
        uucico
        uuxqt
    - In /usr/local/bin, turn on the setuid bit for these binaries:
        sudo chmod +s /usr/local/bin/uu*
      (This is the step that you cannot perform within /usr/bin or /usr/sbin)
    - Add /usr/local/bin to your PATH preceding /usr/bin and /usr/sbin
    - Enable the uucp service:
        sudo launchctl load -w /System/Library/LaunchDaemons/com.apple.uucp.plist

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