By default, pathchk will check each component of each path operand based on the underlying file system. A diagnostic will be written for each path operand that:
- is longer than PATH_MAX bytes.
- contains any component longer than NAME_MAX bytes in its containing directory
- contains any component in a directory that is not searchable
- contains any character in any component that is not valid in its containing directory.
The format of the diagnostic message is not specified, but will indicate the error detected and the corresponding path operand.
It will not be considered an error if one or more components of a path operand do not exist as long as a file matching the path name specified by the missing components could be created that does not violate any of the checks specified above.
- is longer than _POSIX_PATH_MAX bytes
- contains any component longer than _POSIX_NAME_MAX bytes
- contains any character in any component that is not in the portable filename character set.
pax -f archive | sed -e ’/ == .*/s///’ | xargs pathchk if [ $? -eq 0 ] then pax -r -f archive else echo Investigate problems before importing files. exit 1 fi
To verify that all files in the current directory hierarchy could be moved to any system conforming to the X/Open specification that also supports the pax(1) command:
find . -print | xargs pathchk -p if [ $? -eq 0 ] then pax -w -f archive . else echo Portable archive cannot be created. exit 1 fi
To verify that a user-supplied path names a readable file and that the application can create a file extending the given path without truncation and without overwriting any existing file:
case $- in *C*) reset="";; *) reset="set +C" set -C;; esac test -r "$path" && pathchk "$path.out" && rm "$path.out" > "$path.out" if [ $? -ne 0 ]; then printf "%s: %s not found or %s.out fails \ creation checks.\n" $0 "$path" "$path" $reset # reset the noclobber option in case a trap # on EXIT depends on it exit 1 fi $reset PROCESSING < "$path" > "$path.out"
The following assumptions are made in this example:
rm "$path.out" > "$path.out"
- a.
- The pathchk command has already verified, at this point, that $path.out will not be truncated.
- b.
- With the noclobber option set, the shell will verify that $path.out does not already exist before invoking rm.
- c.
- If the shell succeeded in creating $path.out, rm will remove it so that the application can create the file again in the PROCESSING step.
- d.
- If the PROCESSING step wants the file to exist already when it is invoked, the:
rm "$path.out" > "$path.out"
should be replaced with:
> "$path.out"
which will verify that the file did not already exist, but leave $path.out in place for use by PROCESSING.