diff --git a/doc_src/doc.hdr b/doc_src/doc.hdr
index 5299b850d..f8ea41985 100644
--- a/doc_src/doc.hdr
+++ b/doc_src/doc.hdr
@@ -1111,8 +1111,7 @@ g++, javac, java, gcj, lpr, doxygen, whois, find)
 \subsection bugs Known bugs
 
 - Completion for gcc -\#\#\# option doesn't work.
-- Many completions are made specifically for the GNU 
-version of a POSIX command
+- Many completions are made specifically for the GNU version of a POSIX command
 - Yanking weird characters from clipboard prints Unicode escapes
 - Suspending and then resuming pipelines containing a builtin seems to be broken.
 - Interactive input seems broken inside blocks. Is local echo and other terminal values not restored when in an interactive block?
diff --git a/init/completions/df.fish b/init/completions/df.fish
index dc3b77fb5..d950a42b6 100644
--- a/init/completions/df.fish
+++ b/init/completions/df.fish
@@ -1,18 +1,43 @@
+#
+# Completions for df
+#
+
+#
+# Completions for mount define the $__fish_filesystems variable
+#
 complete -y mount
 
-complete -c df -s a -l all -d (_ "Include empty filesystems")
-complete -c df -s B -l block-size -r -d (_ "Block size")
-complete -c df -s h -l human-readable -d (_ "Human readable sizes")
-complete -c df -s H -l si -d (_ "Human readable sizes, powers of 1000")
-complete -c df -s i -l inodes -d (_ "List inode information")
-complete -c df -s k -d (_ "Use 1kB block size")
-complete -c df -s l -l local -d (_ "List only local filesystems")
-complete -c df -l no-sync -d (_ "Do not sync before getting usage info")
-complete -c df -s P -l portability -d (_ "Use Posix format")
-complete -c df -l sync -d (_ "Sync before getting usage info")
-complete -c df -s t -l type -r -d (_ "Filesystem type") -x -a $__fish_filesystems
-complete -c df -s T -l print-type -d (_ "Print filesystem type")
-complete -c df -s x -l exclude-type -d (_ "Excluded filesystem type") -r -x -a $__fish_filesystems
-complete -c df -l help -d (_ "Display help and exit")
-complete -c df -l version -d (_ "Display version and exit")
+#
+# Test if we are using GNU sed
+#
 
+set -l is_gnu 
+df --version >/dev/null ^/dev/null; and set is_gnu --is-gnu
+
+__fish_gnu_complete -c df -s h -l human-readable -d (_ "Human readable sizes") $is_gnu
+__fish_gnu_complete -c df -s i -l inodes -d (_ "List inode information") $is_gnu
+__fish_gnu_complete -c df -s k -d (_ "Use 1kB block size") $is_gnu
+__fish_gnu_complete -c df -s l -l local -d (_ "List only local filesystems") $is_gnu
+__fish_gnu_complete -c df -s P -l portability -d (_ "Use Posix format") $is_gnu
+__fish_gnu_complete -c df -s t -l type -r -d (_ "Show filesystems of specified type") $is_gnu -x -a $__fish_filesystems
+
+if test -n "$is_gnu"
+
+	complete -c df -s a -l all -d (_ "Include empty filesystems")
+	complete -c df -s B -l block-size -r -d (_ "Block size")
+	complete -c df -s H -l si -d (_ "Human readable sizes, powers of 1000")
+	complete -c df -l no-sync -d (_ "Do not sync before getting usage info")
+	complete -c df -l sync -d (_ "Sync before getting usage info")
+	complete -c df -s T -l print-type -d (_ "Print filesystem type")
+	complete -c df -s x -l exclude-type -d (_ "Excluded filesystem type") -r -x -a $__fish_filesystems
+	complete -c df -l help -d (_ "Display help and exit")
+	complete -c df -l version -d (_ "Display version and exit")
+
+else
+
+	complete -c df -s a -d (_ "Show all filesystems")
+	complete -c df -s g -d (_ "Show sizes in gigabytes")
+	complete -c df -s m -d (_ "Show sizes in megabytes")
+	complete -c df -s n -d (_ "Print out the previously obtained statistics from the file systems")
+
+end
diff --git a/init/completions/grep.fish b/init/completions/grep.fish
index b29493b38..de96facf2 100644
--- a/init/completions/grep.fish
+++ b/init/completions/grep.fish
@@ -1,3 +1,6 @@
+#
+# Completions for the grep command
+#
 
 complete -c grep -s A -l after-context -d (_ "Print NUM lines of trailing context")
 complete -c grep -s a -l text -d (_ "Process binary file as text")
diff --git a/init/completions/ls.fish b/init/completions/ls.fish
index af45e224a..a217c3cd0 100644
--- a/init/completions/ls.fish
+++ b/init/completions/ls.fish
@@ -1,75 +1,106 @@
+#
+# Completions for the ls command and its aliases
+#
+
+# Test if we are using GNU ls
+
+set -l is_gnu 
+ls --version >/dev/null ^/dev/null; and set is_gnu --is-gnu
 
 for i in ls ll la
 
-	complete -c $i -s a -l all -d (_ "Show hidden")
-	complete -c $i -s A -l almost-all -d (_ "Show hidden except . and ..")
-	complete -c $i -l author -d (_ "Print author")
-	complete -c $i -s b -l escape -d (_ "Octal escapes for non graphic")
-	complete -c $i -l blocksize -x -d (_ "Set block size")
-	complete -c $i -s B -l ignore-backups -d (_ "Ignore files ending with ~")
-	complete -c $i -s c -d (_ "Show and sort by ctime")
-	complete -c $i -s C -d (_ "List by columns")
-	complete -c $i -l color -f -a "never always auto" -d (_ "Use colors")
-	complete -c $i -s d -l directory -d (_ "List directories, not their content")
-	complete -c $i -s D -l dired -d (_ "Generate dired output")
-	complete -c $i -s f -d (_ "Don't sort")
-	complete -c $i -s F -l classify -d (_ "Append filetype indicator")
-	complete -c $i -l format -x -a "across commas horizontal long single-column verbose vertical" -d (_ "List format")
-	complete -c $i -l full-time -d (_ "Long format, full-iso time")
-	complete -c $i -s g -d (_ "Long format without owner")
-	complete -c $i -s G -l no-group -d (_ "Don't print group information")
-	complete -c $i -s h -l human-readable -d (_ "Human readable sizes")
-	complete -c $i -l si -d (_ "Human readable sizes, powers of 1000")
-	complete -c $i -s H -l dereference-command-line -d (_ "Follow symlinks")
-	complete -c $i -l dereference-command-line-symlink-to-dir #-d (_ "Follow directory symlinks from command line")
-	complete -c $i -l indicator-style -x -a "none classify file-type" -d (_ "Append filetype indicator")
-	complete -c $i -s i -l inode -d (_ "Print inode number of files")
-	complete -c $i -s I -l ignore -r -d (_ "Skip entries matching pattern")
-	complete -c $i -s k -d (_ "Like --block-size=1K")
-	complete -c $i -s l -d (_ "Long format")
-	complete -c $i -s L -l dereference -d (_ "Follow symlinks")
-	complete -c $i -s m -d (_ "Comma separated format")
-	complete -c $i -s n -l numeric-uid-gid -d (_ "Long format, numeric IDs")
-	complete -c $i -s N -l literal -d (_ "Print raw entry names")
-	complete -c $i -s o -d (_ "Long format without groups")
-	complete -c $i -s p -l file-type -d (_ "Append filetype indicator")
-	complete -c $i -s q -l hide-control-chars -d (_ "Replace non-graphic characters with '?'")
-	complete -c $i -l show-control-chars -d (_ "Non graphic as-is")
-	complete -c $i -s Q -l quote-name -d (_ "Enclose entry in quotes")
-	complete -c $i -l quoting-style -x -a "literal locale shell shell-always c escape" -d (_ "Select quoting style")
-	complete -c $i -s r -l reverse -d (_ "Reverse sort order")
-	complete -c $i -s R -l recursive -d (_ "List subdirectory recursively")
-	complete -c $i -s s -l size -d (_ "Print size of files")
-	complete -c $i -s S -d (_ "Sort by size")
-	complete -c $i -l sort -x -d (_ "Sort criteria") -a "
-	extension\t'Sort by file extension'
-	none\tDon't\ sort
-		size\t'Sort by size'
-		time\t'Sort by modification time'
-		version\t'Sort by version'
-		status\t'Sort by file status modification time'
-		atime\t'Sort by access time'
-		access\t'Sort by access time'
-		use\t'Sort by access time'
-	"
-	complete -c $i -l time -x -d (_ "Show time type") -a "
-		time\t'Sort by modification time'
-		access\t'Sort by access time'
-		use\t'Sort by use time'
-		ctime\t'Sort by file status modification time'
-		status\t'Sort by status time'
-	"
-	complete -c $i -l time-style -x -a "full-iso long-iso iso locale" -d (_ "Select time style")
-	complete -c $i -s t -d (_ "Sort by modification time")
-	complete -c $i -s T -l tabsize -x -a "1 2 3 4 5 6 7 8 9 10 11 12" -d (_ "Assume tab stops at each COLS")
-	complete -c $i -s u -d (_ "Show access time")
-	complete -c $i -s U -d (_ "Do not sort")
-	complete -c $i -s v -d (_ "Sort by version")
-	complete -c $i -s w -l width -x -d (_ "Assume screen width")
-	complete -c $i -s x -d (_ "List entries by lines")
-	complete -c $i -s X -d (_ "Sort by extension")
-	complete -c $i -s 1 -d (_ "List one file per line")
-	complete -c $i -l help -d (_ "Display help and exit")
-	complete -c $i -l version -d (_ "Display version and exit")
+	# Shared ls switches
 
+	__fish_gnu_complete -c $i -s a -l all -d (_ "Show hidden") $is_gnu
+	__fish_gnu_complete -c $i -s A -l almost-all -d (_ "Show hidden except . and ..") $is_gnu
+	__fish_gnu_complete -c $i -s F -l classify -d (_ "Append filetype indicator") $is_gnu
+	__fish_gnu_complete -c $i -s H -l dereference-command-line -d (_ "Follow symlinks") $is_gnu
+	__fish_gnu_complete -c $i -s L -l dereference -d (_ "Follow symlinks") $is_gnu
+	__fish_gnu_complete -c $i -s R -l recursive -d (_ "List subdirectory recursively") $is_gnu
+	__fish_gnu_complete -c $i -s b -l escape -d (_ "Octal escapes for non graphic characters") $is_gnu
+	__fish_gnu_complete -c $i -s d -l directory -d (_ "List directories, not their content") $is_gnu
+	__fish_gnu_complete -c $i -s h -l human-readable -d (_ "Human readable sizes") $is_gnu
+	__fish_gnu_complete -c $i -s i -l inode -d (_ "Print inode number of files") $is_gnu
+	__fish_gnu_complete -c $i -s n -l numeric-uid-gid -d (_ "Long format, numeric IDs") $is_gnu
+	__fish_gnu_complete -c $i -s p -l file-type -d (_ "Append filetype indicator") $is_gnu
+	__fish_gnu_complete -c $i -s q -l hide-control-chars -d (_ "Replace non-graphic characters with '?'") $is_gnu
+	__fish_gnu_complete -c $i -s r -l reverse -d (_ "Reverse sort order") $is_gnu
+	__fish_gnu_complete -c $i -s s -l size -d (_ "Print size of files") $is_gnu
+
+	complete -c $i -s C -d (_ "List by columns")
+	complete -c $i -s S -d (_ "Sort by size")
+	complete -c $i -s c -d (_ "Show and sort by ctime")
+	complete -c $i -s f -d (_ "Don't sort")
+	complete -c $i -s g -d (_ "Long format without owner")
+	complete -c $i -s k -d (_ "Set blocksize to 1kB")
+	complete -c $i -s l -d (_ "Long format")
+	complete -c $i -s m -d (_ "Comma separated format")
+	complete -c $i -s t -d (_ "Sort by modification time")
+	complete -c $i -s u -d (_ "Show access time")
+	complete -c $i -s x -d (_ "List entries by lines")
+	complete -c $i -s 1 -d (_ "List one file per line")
+
+	if test -n "$is_gnu"
+
+		# GNU specific features
+
+		complete -c $i -l author -d (_ "Print author")
+		complete -c $i -l blocksize -x -d (_ "Set block size")
+		complete -c $i -s B -l ignore-backups -d (_ "Ignore files ending with ~")
+		complete -c $i -l color -f -a "never always auto" -d (_ "Use colors")
+		complete -c $i -s D -l dired -d (_ "Generate dired output")
+		complete -c $i -l format -x -a "across commas horizontal long single-column verbose vertical" -d (_ "List format")
+		complete -c $i -l full-time -d (_ "Long format, full-iso time")
+		complete -c $i -s G -l no-group -d (_ "Don't print group information")
+		complete -c $i -l si -d (_ "Human readable sizes, powers of 1000")
+		complete -c $i -l dereference-command-line-symlink-to-dir #-d (_ "Follow directory symlinks from command line")
+		complete -c $i -l indicator-style -x -a "none classify file-type" -d (_ "Append filetype indicator")
+		complete -c $i -s I -l ignore -r -d (_ "Skip entries matching pattern")
+		complete -c $i -s N -l literal -d (_ "Print raw entry names")
+		complete -c $i -s o -d (_ "Long format without groups")
+		complete -c $i -l show-control-chars -d (_ "Non graphic as-is")
+		complete -c $i -s Q -l quote-name -d (_ "Enclose entry in quotes")
+		complete -c $i -l quoting-style -x -a "literal locale shell shell-always c escape" -d (_ "Select quoting style")
+		complete -c $i -l sort -x -d (_ "Sort criteria") -a "
+			extension\t'Sort by file extension'
+			none\tDon't\ sort
+			size\t'Sort by size'
+			time\t'Sort by modification time'
+			version\t'Sort by version'
+			status\t'Sort by file status modification time'
+			atime\t'Sort by access time'
+			access\t'Sort by access time'
+			use\t'Sort by access time'
+		"
+		complete -c $i -l time -x -d (_ "Show time type") -a "
+			time\t'Sort by modification time'
+			access\t'Sort by access time'
+			use\t'Sort by use time'
+			ctime\t'Sort by file status modification time'
+			status\t'Sort by status time'
+		"
+		complete -c $i -l time-style -x -a "full-iso long-iso iso locale" -d (_ "Select time style")
+		complete -c $i -s T -l tabsize -x -a "1 2 3 4 5 6 7 8 9 10 11 12" -d (_ "Assume tab stops at each COLS")
+		complete -c $i -s U -d (_ "Do not sort")
+		complete -c $i -s v -d (_ "Sort by version")
+		complete -c $i -s w -l width -x -d (_ "Assume screen width")
+		complete -c $i -s X -d (_ "Sort by extension")
+		complete -c $i -l help -d (_ "Display help and exit")
+		complete -c $i -l version -d (_ "Display version and exit")
+
+	else
+
+		# If not a GNU system, assume we have standard BSD ls features instead
+
+		complete -c $i -s B -d (_ "Octal escapes for non graphic characters")
+		complete -c $i -s G -d (_ "Use colors")
+		complete -c $i -s I -d (_ "Prevent -A from being automatically set for root")
+		complete -c $i -s P -d (_ "Don't follow symlinks")
+		complete -c $i -s T -d (_ "Show modification time")
+		complete -c $i -s W -d (_ "Show whiteouts when scanning directories")
+		complete -c $i -s Z -d (_ "Display each file's MAC label")
+		complete -c $i -s o -d (_ "Include the file flags in a long (-l) output")
+		complete -c $i -s w -d (_ "Print raw entry names")
+
+	end
 end
diff --git a/init/completions/sed.fish b/init/completions/sed.fish
index 54c2c9529..00180c68d 100644
--- a/init/completions/sed.fish
+++ b/init/completions/sed.fish
@@ -1,12 +1,38 @@
-complete -c sed -s n -l quiet -d (_ "Silent mode")
-complete -c sed -l silent -d (_ "Silent mode")
-complete -c sed -s e -l expression -x -d (_ "Evaluate expression")
-complete -c sed -s f -l file -r -d (_ "Evalute file")
-complete -c sed -s i -l in-place -d (_ "Edit files in place")
-complete -c sed -s l -l line-length -x -d (_ "Specify line-length")
-complete -c sed -l posix -d (_ "Disable all GNU extensions")
-complete -c sed -s r -l regexp-extended -d (_ "Use extended regexp")
-complete -c sed -s s -l separate -d (_ "Consider files as separate")
-complete -c sed -s u -l unbuffered -d (_ "Use minimal IO buffers")
-complete -c sed -l help -d (_ "Display help and exit")
-complete -c sed -s V -l version -d (_ "Display version and exit")
+#
+# Completions for sed
+#
+
+# Test if we are using GNU sed
+
+set -l is_gnu 
+sed --vvversion >/dev/null ^/dev/null; and set is_gnu --is-gnu
+
+# Shared ls switches
+
+__fish_gnu_complete -c sed -s n -l quiet -d (_ "Silent mode") $is_gnu 
+__fish_gnu_complete -c sed -s e -l expression -x -d (_ "Evaluate expression") $is_gnu
+__fish_gnu_complete -c sed -s f -l file -r -d (_ "Evalute file") $is_gnu
+__fish_gnu_complete -c sed -s i -l in-place -d (_ "Edit files in place") $is_gnu
+
+if test -n "$is_gnu"
+
+	# GNU specific features
+
+	complete -c sed -l silent -d (_ "Silent mode")
+	complete -c sed -s l -l line-length -x -d (_ "Specify line-length")
+	complete -c sed -l posix -d (_ "Disable all GNU extensions")
+	complete -c sed -s r -l regexp-extended -d (_ "Use extended regexp")
+	complete -c sed -s s -l separate -d (_ "Consider files as separate")
+	complete -c sed -s u -l unbuffered -d (_ "Use minimal IO buffers")
+	complete -c sed -l help -d (_ "Display help and exit")
+	complete -c sed -s V -l version -d (_ "Display version and exit")
+
+else
+
+	# If not a GNU system, assume we have standard BSD ls features instead
+
+	complete -c sed -s E -d (_ "Use extended regexp")
+	complete -c sed -s a -d (_ "Delay opening files until a command containing the related 'w' function is applied")
+	complete -c sed -s l -d (_ "Use line buffering")
+
+end
diff --git a/init/fish_complete.fish.in b/init/fish_complete.fish.in
index f893186af..9c15be7e5 100644
--- a/init/fish_complete.fish.in
+++ b/init/fish_complete.fish.in
@@ -237,6 +237,35 @@ function __fish_append -d "Internal completion function for appending string to
 	printf "%s\n" "$str"$argv "$str"(printf "%s\n" $argv|sed -e "s/\(\t\|\$\)/,\1/") 
 end
 
+function __fish_gnu_complete -d "Wrapper for the complete builtin. Skips the long completions on non-GNU systems"
+	set is_gnu 0
+
+	# Check if we are using a gnu system
+	for i in (seq (count $argv))
+		switch  $argv[$i]
+			
+			case -g --is-gnu
+				set -e argv[$i]
+				set is_gnu 1
+				break
+		end
+	end
+
+	# Remove long option if not on a gnu system
+	if test $is_gnu = 0
+		for i in (seq (count $argv))
+			if test $argv[$i] = -l
+				set -e argv[$i]
+				set -e argv[$i]
+				break
+			end
+		end
+	end
+	
+	complete $argv
+
+end
+
 #
 # Completions for SysV startup scripts
 #