Path manipulation with bash vars

bash-path-vars

$ FILE=/some/path/to/file.txt

###################################
### Remove matching suffix pattern
###################################

$ echo ${FILE%.*}          # remove ext 
/some/path/to/file

$ FILE=/some/path/to/file.txt.jpg.gpg    # note various file exts
$ echo ${FILE%%.*}                       # remove all exts
/some/path/to/file

$ FILE=/some/path/to/file.txt    # back to inital value
$ echo ${FILE%/*}                # dirname (same as "dirname $FILE")
/some/path/to

$ echo "[ ${FILE%%/*} ]"    # enclosing value with [ ] to clarify
[  ]                        # no value at all

##################################
### Remove matching prefix pattern
##################################

$ echo ${FILE#/some}          # remove root dir only (nice to join paths)
/path/to/file.txt

$ echo /root/dir/${FILE#/some/path/}  # removing prefix path and join to arbitrary prefix dir
/root/dir/to/file.txt

$ echo ${FILE##*/}            # remove all dirs (same as "basename $FILE")
file.txt

##################################
### Check for a given extension
##################################

$ if [ "${FILE/*.txt/1}" == '1' ]; then
> echo match
> else
> echo nope
> fi
match

$ if [ "${FILE/*.conf/1}" == '1' ]; then
> echo match
> else
> echo nope
> fi
nope

# And here is a nice little function:

$ function ext_is() { [ "${1/*.$2/1}" == '1' ]; }
$ ext_is $FILE txt && echo match || echo nope
match
$ ext_is $FILE conf && echo match || echo nope
nope