369 lines
		
	
	
	
		
			11 KiB
		
	
	
	
		
			Sed
		
	
	
	
	
	
			
		
		
	
	
			369 lines
		
	
	
	
		
			11 KiB
		
	
	
	
		
			Sed
		
	
	
	
	
	
#------------------------------------------------------------------------------
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# Detect broken &&-chains in tests.
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#
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# At present, only &&-chains in subshells are examined by this linter;
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# top-level &&-chains are instead checked directly by the test framework. Like
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# the top-level &&-chain linter, the subshell linter (intentionally) does not
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# check &&-chains within {...} blocks.
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#
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# Checking for &&-chain breakage is done line-by-line by pure textual
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# inspection.
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#
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# Incomplete lines (those ending with "\") are stitched together with following
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# lines to simplify processing, particularly of "one-liner" statements.
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# Top-level here-docs are swallowed to avoid false positives within the
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# here-doc body, although the statement to which the here-doc is attached is
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# retained.
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#
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# Heuristics are used to detect end-of-subshell when the closing ")" is cuddled
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# with the final subshell statement on the same line:
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#
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#    (cd foo &&
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#        bar)
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#
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# in order to avoid misinterpreting the ")" in constructs such as "x=$(...)"
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# and "case $x in *)" as ending the subshell.
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#
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# Lines missing a final "&&" are flagged with "?!AMP?!", and lines which chain
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# commands with ";" internally rather than "&&" are flagged "?!SEMI?!". A line
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# may be flagged for both violations.
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#
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# Detection of a missing &&-link in a multi-line subshell is complicated by the
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# fact that the last statement before the closing ")" must not end with "&&".
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# Since processing is line-by-line, it is not known whether a missing "&&" is
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# legitimate or not until the _next_ line is seen. To accommodate this, within
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# multi-line subshells, each line is stored in sed's "hold" area until after
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# the next line is seen and processed. If the next line is a stand-alone ")",
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# then a missing "&&" on the previous line is legitimate; otherwise a missing
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# "&&" is a break in the &&-chain.
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#
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#    (
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#         cd foo &&
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#         bar
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#    )
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#
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# In practical terms, when "bar" is encountered, it is flagged with "?!AMP?!",
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# but when the stand-alone ")" line is seen which closes the subshell, the
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# "?!AMP?!" violation is removed from the "bar" line (retrieved from the "hold"
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# area) since the final statement of a subshell must not end with "&&". The
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# final line of a subshell may still break the &&-chain by using ";" internally
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# to chain commands together rather than "&&", so "?!SEMI?!" is never removed
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# from a line (even though "?!AMP?!" might be).
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#
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# Care is taken to recognize the last _statement_ of a multi-line subshell, not
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# necessarily the last textual _line_ within the subshell, since &&-chaining
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# applies to statements, not to lines. Consequently, blank lines, comment
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# lines, and here-docs are swallowed (but not the command to which the here-doc
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# is attached), leaving the last statement in the "hold" area, not the last
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# line, thus simplifying &&-link checking.
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#
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# The final statement before "done" in for- and while-loops, and before "elif",
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# "else", and "fi" in if-then-else likewise must not end with "&&", thus
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# receives similar treatment.
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#
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# Swallowing here-docs with arbitrary tags requires a bit of finesse. When a
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# line such as "cat <<EOF >out" is seen, the here-doc tag is moved to the front
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# of the line enclosed in angle brackets as a sentinel, giving "<EOF>cat >out".
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# As each subsequent line is read, it is appended to the target line and a
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# (whitespace-loose) back-reference match /^<(.*)>\n\1$/ is attempted to see if
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# the content inside "<...>" matches the entirety of the newly-read line. For
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# instance, if the next line read is "some data", when concatenated with the
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# target line, it becomes "<EOF>cat >out\nsome data", and a match is attempted
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# to see if "EOF" matches "some data". Since it doesn't, the next line is
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# attempted. When a line consisting of only "EOF" (and possible whitespace) is
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# encountered, it is appended to the target line giving "<EOF>cat >out\nEOF",
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# in which case the "EOF" inside "<...>" does match the text following the
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# newline, thus the closing here-doc tag has been found. The closing tag line
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# and the "<...>" prefix on the target line are then discarded, leaving just
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# the target line "cat >out".
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#
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# To facilitate regression testing (and manual debugging), a ">" annotation is
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# applied to the line containing ")" which closes a subshell, ">>" to a line
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# closing a nested subshell, and ">>>" to a line closing both at once. This
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# makes it easy to detect whether the heuristics correctly identify
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# end-of-subshell.
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#------------------------------------------------------------------------------
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# incomplete line -- slurp up next line
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:squash
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/\\$/ {
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	N
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	s/\\\n//
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	bsquash
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}
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# here-doc -- swallow it to avoid false hits within its body (but keep the
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# command to which it was attached)
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/<<[ 	]*[-\\'"]*[A-Za-z0-9_]/ {
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	s/^\(.*\)<<[ 	]*[-\\'"]*\([A-Za-z0-9_][A-Za-z0-9_]*\)['"]*/<\2>\1<</
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	s/[ 	]*<<//
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	:hered
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	N
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	/^<\([^>]*\)>.*\n[ 	]*\1[ 	]*$/!{
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		s/\n.*$//
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		bhered
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	}
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	s/^<[^>]*>//
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	s/\n.*$//
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}
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# one-liner "(...) &&"
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/^[ 	]*!*[ 	]*(..*)[ 	]*&&[ 	]*$/boneline
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# same as above but without trailing "&&"
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/^[ 	]*!*[ 	]*(..*)[ 	]*$/boneline
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# one-liner "(...) >x" (or "2>x" or "<x" or "|x" or "&"
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/^[ 	]*!*[ 	]*(..*)[ 	]*[0-9]*[<>|&]/boneline
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# multi-line "(...\n...)"
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/^[ 	]*(/bsubshell
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# innocuous line -- print it and advance to next line
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b
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# found one-liner "(...)" -- mark suspect if it uses ";" internally rather than
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# "&&" (but not ";" in a string)
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:oneline
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/;/{
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	/"[^"]*;[^"]*"/!s/^/?!SEMI?!/
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}
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b
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:subshell
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# bare "(" line? -- stash for later printing
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/^[ 	]*([	]*$/ {
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	h
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	bnextline
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}
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# "(..." line -- split off and stash "(", then process "..." as its own line
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x
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s/.*/(/
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x
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s/(//
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bslurp
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:nextline
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N
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s/.*\n//
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:slurp
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# incomplete line "...\"
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/\\$/bicmplte
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# multi-line quoted string "...\n..."?
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/"/bdqstring
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# multi-line quoted string '...\n...'? (but not contraction in string "it's")
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/'/{
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	/"[^'"]*'[^'"]*"/!bsqstring
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}
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:folded
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# here-doc -- swallow it
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/<<[ 	]*[-\\'"]*[A-Za-z0-9_]/bheredoc
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# comment or empty line -- discard since final non-comment, non-empty line
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# before closing ")", "done", "elsif", "else", or "fi" will need to be
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# re-visited to drop "suspect" marking since final line of those constructs
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# legitimately lacks "&&", so "suspect" mark must be removed
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/^[ 	]*#/bnextline
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/^[ 	]*$/bnextline
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# in-line comment -- strip it (but not "#" in a string, Bash ${#...} array
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# length, or Perforce "//depot/path#42" revision in filespec)
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/[ 	]#/{
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	/"[^"]*#[^"]*"/!s/[ 	]#.*$//
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}
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# one-liner "case ... esac"
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/^[ 	]*case[ 	]*..*esac/bchkchn
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# multi-line "case ... esac"
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/^[ 	]*case[ 	]..*[ 	]in/bcase
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# multi-line "for ... done" or "while ... done"
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/^[ 	]*for[ 	]..*[ 	]in/bcontinue
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/^[ 	]*while[ 	]/bcontinue
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/^[ 	]*do[ 	]/bcontinue
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/^[ 	]*do[ 	]*$/bcontinue
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/;[ 	]*do/bcontinue
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/^[ 	]*done[ 	]*&&[ 	]*$/bdone
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/^[ 	]*done[ 	]*$/bdone
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/^[ 	]*done[ 	]*[<>|]/bdone
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/^[ 	]*done[ 	]*)/bdone
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/||[ 	]*exit[ 	]/bcontinue
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/||[ 	]*exit[ 	]*$/bcontinue
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# multi-line "if...elsif...else...fi"
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/^[ 	]*if[ 	]/bcontinue
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/^[ 	]*then[ 	]/bcontinue
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/^[ 	]*then[ 	]*$/bcontinue
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/;[ 	]*then/bcontinue
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/^[ 	]*elif[ 	]/belse
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/^[ 	]*elif[ 	]*$/belse
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/^[ 	]*else[ 	]/belse
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/^[ 	]*else[ 	]*$/belse
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/^[ 	]*fi[ 	]*&&[ 	]*$/bdone
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/^[ 	]*fi[ 	]*$/bdone
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/^[ 	]*fi[ 	]*[<>|]/bdone
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/^[ 	]*fi[ 	]*)/bdone
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# nested one-liner "(...) &&"
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/^[ 	]*(.*)[ 	]*&&[ 	]*$/bchkchn
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# nested one-liner "(...)"
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/^[ 	]*(.*)[ 	]*$/bchkchn
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# nested one-liner "(...) >x" (or "2>x" or "<x" or "|x")
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/^[ 	]*(.*)[ 	]*[0-9]*[<>|]/bchkchn
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# nested multi-line "(...\n...)"
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/^[ 	]*(/bnest
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# multi-line "{...\n...}"
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/^[ 	]*{/bblock
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# closing ")" on own line -- exit subshell
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/^[ 	]*)/bclssolo
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# "$((...))" -- arithmetic expansion; not closing ")"
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/\$(([^)][^)]*))[^)]*$/bchkchn
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# "$(...)" -- command substitution; not closing ")"
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/\$([^)][^)]*)[^)]*$/bchkchn
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# multi-line "$(...\n...)" -- command substitution; treat as nested subshell
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/\$([^)]*$/bnest
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# "=(...)" -- Bash array assignment; not closing ")"
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/=(/bchkchn
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# closing "...) &&"
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/)[ 	]*&&[ 	]*$/bclose
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# closing "...)"
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/)[ 	]*$/bclose
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# closing "...) >x" (or "2>x" or "<x" or "|x")
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/)[ 	]*[<>|]/bclose
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:chkchn
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# mark suspect if line uses ";" internally rather than "&&" (but not ";" in a
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# string and not ";;" in one-liner "case...esac")
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/;/{
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	/;;/!{
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		/"[^"]*;[^"]*"/!s/^/?!SEMI?!/
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	}
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}
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# line ends with pipe "...|" -- valid; not missing "&&"
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/|[ 	]*$/bcontinue
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# missing end-of-line "&&" -- mark suspect
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/&&[ 	]*$/!s/^/?!AMP?!/
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:continue
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# retrieve and print previous line
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x
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n
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bslurp
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# found incomplete line "...\" -- slurp up next line
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:icmplte
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N
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s/\\\n//
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bslurp
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# check for multi-line double-quoted string "...\n..." -- fold to one line
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:dqstring
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# remove all quote pairs
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s/"\([^"]*\)"/@!\1@!/g
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# done if no dangling quote
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/"/!bdqdone
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# otherwise, slurp next line and try again
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N
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s/\n//
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bdqstring
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:dqdone
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s/@!/"/g
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bfolded
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# check for multi-line single-quoted string '...\n...' -- fold to one line
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:sqstring
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# remove all quote pairs
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s/'\([^']*\)'/@!\1@!/g
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# done if no dangling quote
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/'/!bsqdone
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# otherwise, slurp next line and try again
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N
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s/\n//
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bsqstring
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:sqdone
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s/@!/'/g
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bfolded
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# found here-doc -- swallow it to avoid false hits within its body (but keep
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# the command to which it was attached)
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:heredoc
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s/^\(.*\)<<[ 	]*[-\\'"]*\([A-Za-z0-9_][A-Za-z0-9_]*\)['"]*/<\2>\1<</
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s/[ 	]*<<//
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:heredsub
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N
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/^<\([^>]*\)>.*\n[ 	]*\1[ 	]*$/!{
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	s/\n.*$//
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	bheredsub
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}
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s/^<[^>]*>//
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s/\n.*$//
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bfolded
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# found "case ... in" -- pass through untouched
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:case
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x
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n
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/^[ 	]*esac/bslurp
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bcase
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# found "else" or "elif" -- drop "suspect" from final line before "else" since
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# that line legitimately lacks "&&"
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:else
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x
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s/?!AMP?!//
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x
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bcontinue
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# found "done" closing for-loop or while-loop, or "fi" closing if-then -- drop
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# "suspect" from final contained line since that line legitimately lacks "&&"
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:done
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x
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s/?!AMP?!//
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x
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# is 'done' or 'fi' cuddled with ")" to close subshell?
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/done.*)/bclose
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/fi.*)/bclose
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bchkchn
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# found nested multi-line "(...\n...)" -- pass through untouched
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:nest
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x
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:nstslurp
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n
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# closing ")" on own line -- stop nested slurp
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/^[ 	]*)/bnstclose
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# comment -- not closing ")" if in comment
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/^[ 	]*#/bnstcnt
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# "$((...))" -- arithmetic expansion; not closing ")"
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/\$(([^)][^)]*))[^)]*$/bnstcnt
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# "$(...)" -- command substitution; not closing ")"
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/\$([^)][^)]*)[^)]*$/bnstcnt
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# closing "...)" -- stop nested slurp
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/)/bnstclose
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:nstcnt
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x
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bnstslurp
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:nstclose
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s/^/>>/
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# is it "))" which closes nested and parent subshells?
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/)[ 	]*)/bslurp
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bchkchn
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# found multi-line "{...\n...}" block -- pass through untouched
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:block
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x
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n
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# closing "}" -- stop block slurp
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/}/bchkchn
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bblock
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# found closing ")" on own line -- drop "suspect" from final line of subshell
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# since that line legitimately lacks "&&" and exit subshell loop
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:clssolo
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x
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s/?!AMP?!//
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p
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x
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s/^/>/
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b
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# found closing "...)" -- exit subshell loop
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:close
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x
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p
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x
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s/^/>/
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b
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