The df command shows available disk space.
However, the extension might be corrupted due to network issues. If you're sure you didn't ran out of space, delete it while it's not mounted and download again.
It looks like I have not run out of space (see below). I have not mounted it yet. How can I delete it and reinstall it?
tc@box:~$ df
Filesystem Size Used Available Use% Mounted on
tmpfs 391.1M 21.9M 369.2M 6% /
tmpfs 217.3M 0 217.3M 0% /dev/shm
/dev/mmcblk0p2 7.2G 63.6M 6.9G 1% /mnt/mmcblk0p2
/dev/loop0 1.1M 1.1M 0 100% /tmp/tcloop/mc
/dev/loop1 1.9M 1.9M 0 100% /tmp/tcloop/openssh
/dev/loop2 128.0K 128.0K 0 100% /tmp/tcloop/alsa
/dev/loop3 1.1M 1.1M 0 100% /tmp/tcloop/alsa-utils
/dev/loop4 128.0K 128.0K 0 100% /tmp/tcloop/make
/dev/loop5 27.9M 27.9M 0 100% /tmp/tcloop/gcc
/dev/loop6 256.0K 256.0K 0 100% /tmp/tcloop/tar
/dev/loop7 128.0K 128.0K 0 100% /tmp/tcloop/acl
/dev/loop8 128.0K 128.0K 0 100% /tmp/tcloop/wiringpi
/dev/loop9 128.0K 128.0K 0 100% /tmp/tcloop/nano
/dev/loop10 128.0K 128.0K 0 100% /tmp/tcloop/wireless_too ls
/dev/loop11 384.0K 384.0K 0 100% /tmp/tcloop/wpa_supplica nt
/dev/loop12 8.0K 8.0K 0 100% /tmp/tcloop/wifi
/dev/loop13 1.1M 1.1M 0 100% /tmp/tcloop/glib2
/dev/loop14 128.0K 128.0K 0 100% /tmp/tcloop/libssh2
/dev/loop15 256.0K 256.0K 0 100% /tmp/tcloop/ncurses
/dev/loop16 128.0K 128.0K 0 100% /tmp/tcloop/libedit
/dev/loop17 1.1M 1.1M 0 100% /tmp/tcloop/openssl
/dev/loop18 384.0K 384.0K 0 100% /tmp/tcloop/libasound
/dev/loop19 512.0K 512.0K 0 100% /tmp/tcloop/isl
/dev/loop20 128.0K 128.0K 0 100% /tmp/tcloop/mpc
/dev/loop21 128.0K 128.0K 0 100% /tmp/tcloop/libacl
/dev/loop22 384.0K 384.0K 0 100% /tmp/tcloop/file
/dev/loop23 384.0K 384.0K 0 100% /tmp/tcloop/ncurses-term info
/dev/loop24 128.0K 128.0K 0 100% /tmp/tcloop/libiw
/dev/loop25 2.8M 2.8M 0 100% /tmp/tcloop/wireless-4.4 .20-piCore+
/dev/loop26 256.0K 256.0K 0 100% /tmp/tcloop/libnl
/dev/loop27 116.0K 116.0K 0 100% /tmp/tcloop/readline
/dev/loop28 128.0K 128.0K 0 100% /tmp/tcloop/gamin
/dev/loop29 128.0K 128.0K 0 100% /tmp/tcloop/libelf
/dev/loop30 384.0K 384.0K 0 100% /tmp/tcloop/pcre
/dev/loop31 384.0K 384.0K 0 100% /tmp/tcloop/libgcrypt
/dev/loop32 640.0K 640.0K 0 100% /tmp/tcloop/ca-certifica tes
/dev/loop33 768.0K 768.0K 0 100% /tmp/tcloop/alsa-modules -4.4.20-piCore+
/dev/loop34 256.0K 256.0K 0 100% /tmp/tcloop/gmp
/dev/loop35 256.0K 256.0K 0 100% /tmp/tcloop/mpfr
/dev/loop36 128.0K 128.0K 0 100% /tmp/tcloop/libattr
/dev/loop37 128.0K 128.0K 0 100% /tmp/tcloop/bzip2-lib
/dev/loop38 128.0K 128.0K 0 100% /tmp/tcloop/libgpg-error
tc@box:~$