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a='\*bc'
b='\'
c='*'
echo "a is '$a'"
echo "b is '$b'"
echo "c is '$c'"
echo '${a##?*} removes everything: '"|${a##?*}|"' - matches one char, then all'
echo '${a##?"*"} removes \*: '"|${a##?"*"}|"' - matches one char, then *'
echo '${a##\*} removes nothing: '"|${a##\*}|"' - first char is not *'
echo '${a##\\*} removes everything: '"|${a##\\*}|"' - matches \, then all'
echo '${a##\\\*} removes \*: '"|${a##\\\*}|"' - matches \, then *'
echo '${a##?$c} removes everything: '"|${a##?$c}|"' - matches one char, then all'
echo '${a##?"$c"} removes \*: '"|${a##?"$c"}|"' - matches one char, then *'
echo '${a##\\$c} removes everything: '"|${a##\\$c}|"' - matches \, then all'
echo '${a##\\\$c} removes nothing: '"|${a##\\\$c}|"' - matches \, but then second char is not $'
echo '${a##\\"$c"} removes \*: '"|${a##\\"$c"}|"' - matches \, then *'
echo '${a##$b} removes \: '"|${a##$b}|"' - matches \'
echo '${a##"$b"} removes \: '"|${a##"$b"}|"' - matches \'
echo
sq="'"
echo 'Single quote tests:'
echo '${a##?'$sq'*'$sq'} removes \*: '"|${a##?'*'}|"' - matches one char, then *'
echo '${a##'$sq'\'$sq'*} removes everything: '"|${a##'\'*}|"' - matches \, then all'
echo '${a##'$sq'\'$sq'\*} removes \*: '"|${a##'\'\*}|"' - matches \, then *'
echo '${a##'$sq'\*'$sq'} removes \*: '"|${a##'\*'}|"' - matches \, then *'
echo '${a##'$sq'\'$sq'$c} removes everything: '"|${a##'\'$c}|"' - matches \, then all'
echo '${a##'$sq'\'$sq'\$c} removes nothing: '"|${a##'\'\$c}|"' - matches \, but then second char is not $'
echo '${a##'$sq'\'$sq'"$c"} removes \*: '"|${a##'\'"$c"}|"' - matches \, then *'
echo
## In bash, this isn't working as expected
#echo '${a##$b?} removes \*: '"|${a##$b?}|"' - matches \, then one char' # bash prints |\*bc|
#echo '${a##$b*} removes everything: '"|${a##$b*}|"' - matches \, then all' # bash prints |\*bc|
#echo '${a##$b$c} removes everything: '"|${a##$b$c}|"' - matches \, then all' # bash prints |\*bc|
#echo '${a##$b"$c"} removes \*: '"|${a##$b"$c"}|"' - matches \, then *' # bash prints |\*bc|
## the cause seems to be that $b emits backslash that "glues" onto next character if there is one:
## a='\*bc'; b='\'; c='*'; echo "|${a##?$b*}|" # bash prints |bc| - the $b* works as \* (matches literal *)
## a='\*bc'; b='\'; c='*'; echo "|${a##\\$b*}|" # bash prints |bc|
#echo
echo '${a##"$b"?} removes \*: '"|${a##"$b"?}|"' - matches \, then one char'
echo '${a##"$b"*} removes everything: '"|${a##"$b"*}|"' - matches \, then all'
echo '${a##"$b""?"} removes nothing: '"|${a##"$b""?"}|"' - second char is not ?' # bash prints |bc|
echo '${a##"$b""*"} removes \*: '"|${a##"$b""*"}|"' - matches \, then *'
echo '${a##"$b"\*} removes \*: '"|${a##"$b"\*}|"' - matches \, then *'
echo '${a##"$b"$c} removes everything:'"|${a##"$b"$c}|"' - matches \, then all'
echo '${a##"$b""$c"} removes \*: '"|${a##"$b""$c"}|"' - matches \, then *'
echo '${a##"$b?"} removes nothing: '"|${a##"$b?"}|"' - second char is not ?' # bash prints |bc|
echo '${a##"$b*"} removes \*: '"|${a##"$b*"}|"' - matches \, then *' # bash prints ||
echo '${a##"$b$c"} removes \*: '"|${a##"$b$c"}|"' - matches \, then *'
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