Composer install/update not working
In first place You should try clearing composer cache.
rm -rf ~/.composer/cache
But more probably it's issue connected with available memory. Increasing memory_limit should help.
I had this issue and realised I had xdebug enabled. Disabling it fixed the issue for me.
Try with this one and make sure that the composer.json file exist in your project directory.
COMPOSER=composer.json composer update
Try to view a verbose report:
composer install -vvv
or:
composer update -vvv
If last line shows that process is killed, you need to increase your swap memory:
sudo dd if=/dev/zero of=/swapfile bs=1024 count=512k
sudo chmod 600 /swapfile
sudo mkswap /swapfile
sudo swapon /swapfile
swapon -s
if it continues killing the process, you need to increase 512k to 1024k or maybe 2048k