diff --git a/syntax/c.nanorc b/syntax/c.nanorc
index 14db97c9..9571b3c9 100644
--- a/syntax/c.nanorc
+++ b/syntax/c.nanorc
@@ -33,7 +33,7 @@ color cyan "__attribute__[[:blank:]]*\(\([^)]*\)\)" "__(aligned|asm|builtin|hidd
 color brightyellow ""([^"]|\\")*"" "#[[:blank:]]*include[[:blank:]]*<[^>]+>"
 
 # Preprocessor directives.
-color brightcyan start="^[[:blank:]]*#[[:blank:]]*(if(n?def)?|elif|warning|error|pragma)\>" end="(\`|[^\\])$"
+color brightcyan start="^[[:blank:]]*#[[:blank:]]*(if(n?def)?|elif|warning|error|pragma)\>" end="(\`|[^\])$"
 color brightcyan "^[[:blank:]]*#[[:blank:]]*((define|else|endif|include(_next)?|line|undef)\>|$)"
 
 # Comments.
diff --git a/syntax/extra/gentoo.nanorc b/syntax/extra/gentoo.nanorc
index e03f2e24..a8643f9e 100644
--- a/syntax/extra/gentoo.nanorc
+++ b/syntax/extra/gentoo.nanorc
@@ -11,7 +11,7 @@ color brightgreen "\<default(_pkg_nofetch|_src_(unpack|prepare|configure|compile
 ## Bash-related syntax:
 color green "\<(break|case|continue|do|done|elif|else|esac|exit|fi|for|function|if|in|read|return|select|shift|then|time|until|while)\>"
 color green "\<(declare|eval|exec|export|let|local)\>"
-color green "[{}():;|`$<>!=&\\]" "(\]|\[)"
+color green "[][{}():;|`$<>!=&\]"
 color green "-[defhnrsuwxzL]\>"
 color green "-(eq|ne|gt|lt|ge|le)\>"
 ## Variables... official portage ones in red, all others in bright red:
diff --git a/syntax/nftables.nanorc b/syntax/nftables.nanorc
index a5dcf769..7d65c080 100644
--- a/syntax/nftables.nanorc
+++ b/syntax/nftables.nanorc
@@ -27,7 +27,7 @@ color ,green "[[:space:]]+$"
 
 # Strings and others
 color yellow ""(\\.|[^"])*"" "'(\\.|[^'])*'"
-color green "[{}():;|`$<>!=&\\]" "(\]|\[)"
+color green "[][{}():;|`$<>!=&\]"
 
 # Basic variable names
 color brightred "(\$|@)[[:alpha:]_-][[:alnum:]_.-]*"
diff --git a/syntax/objc.nanorc b/syntax/objc.nanorc
index 6d2a1c9a..65c03b5f 100644
--- a/syntax/objc.nanorc
+++ b/syntax/objc.nanorc
@@ -24,7 +24,7 @@ color magenta "[[:alnum:]]*:"
 color white "\[[^][:blank:]]*\]"
 
 # Strings.
-color brightblack "'([^'\]|(\\["'abfnrtv\\]))'" "'\\(([0-3]?[0-7]{1,2}))'" "'\\x[0-9A-Fa-f]{1,2}'"
+color brightblack "'([^'\]|(\\["'abfnrtv\]))'" "'\\(([0-3]?[0-7]{1,2}))'" "'\\x[0-9A-Fa-f]{1,2}'"
 color brightblack "<[^= 	]*>" ""(\\.|[^"])*""
 color brightblue "@"(\\.|[^"])*""
 
diff --git a/syntax/sh.nanorc b/syntax/sh.nanorc
index 75c54f77..cb7b8f65 100644
--- a/syntax/sh.nanorc
+++ b/syntax/sh.nanorc
@@ -14,7 +14,7 @@ color brightgreen "^[A-Za-z0-9_-]+\(\)"
 # Keywords, symbols, and comparisons.
 color green "\<(break|case|continue|do|done|elif|else|esac|exit|fi|for|function|if|in|read|return|select|shift|then|time|until|while)\>"
 color green "\<(declare|eval|exec|export|let|local)\>"
-color green "[{}():;|`$<>!=&\\]" "(\]|\[)"
+color green "[][{}():;|`$<>!=&\]"
 color green "-(eq|ne|gt|lt|ge|le|ef|ot|nt)\>"
 
 # Short and long options.