Linux shell path intercepts regular expression _linux shell

Recently write script, need to intercept the path parameter that function passes in the script, discover the following more useful method, record below:

File=/dir1/dir2/dir3/my.file.txt

We can replace each of the different values with ${}:

${file#*/}: Take off the first/and the left string: dir1/dir2/dir3/my.file.txt

${file##*/}: Take off the last one/and the string to the left: My.file.txt

${file#*.} : Take off the first one. and its left string: file.txt

${file##*.} : Take off the last one. and its left string: txt

${file%/*}: Take off the last bar/and the string to the right:/DIR1/DIR2/DIR3

${file%%/*}: Get rid of the first/And right string: (null value)

${FILE%.*}: Take off the last one. and the string to the right:/dir1/dir2/dir3/my.file

${FILE%%.*}: Take off the first one. and the string to the right:/dir1/dir2/dir3/my

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