Random Debian etc. commands I usually forget

*nix: Commands

**Ubuntu version**:
`lsb_release -a`

**Amount of ram**:
`lshw -C memory`

**Switch to superuser**:
`sudo su`

**Show linux headers**:
`apt-cache search linux-headers-$(uname -r)`

**Update linux headers**:
`apt-get install linux-headers-generic`

**Show all packages**:
`dpkg --get-selections`

**Amount of space**:
`df -h`

**Find from apt-cache**:
`apt-cache search <something>`

**Find file**:
`find . -name '*.format'`

**Find folder**:
`find . -type d -name '.format'`

**Find files, remove them and their folders (Be careful)**:
`find /path/to/location/ -name '.format' -exec rm -rf {} \;`

**Find files and remove them (Be careful)**:
`find /path/to/location/ -type f -name "filesToFind" -exec rm -f {} \;`

**Set 644 CHMOD to files**:
`sudo find /path/to/location/ -type f -exec chmod 644 {} \;`

**Set 755 CHMOD to folders**:
`sudo find /path/to/location/ -type d -exec chmod 755 {} \;`

**Copy something recursively with SCP and use identity file**:
`sudo scp -i ~/.ssh/id_rsa -r my/folder user@domain:/my/server/folder`

**Sync folder with rsync and use identity file**:
`rsync -avzr --progress --stats -e "ssh -i ~/.ssh/id_rsa -o IdentitiesOnly=yes" my/folder/ user@domain:/my/server/location`