Useful Commands

Data rescue

Have a dying disk? Better get the data off before it's too late! disk1 is the culprit in this example.

dd conv=noerror,sync if=/dev/disk1 of=/Volumes/whatever/backup.dmg

Encrypted and growable (sparse) disk image

(-size specifies max growth)

hdiutil create dmg_name -size 1g -encryption -type SPARSE -fs HFS+ -volname Vault

Global find / replace

perl -pi -e 's/foo/bar/g' file
perl -pi -e 's/mandir=\'\${prefix}\/man\'/mandir=\'\${prefix}\/share\/man\'/g' configure

====Disk Stats==== (zsh)

echo -n "Sum of all HFS and AFP volumes in gigs: " ; x=0 ; df -t hfs,afpfs | grep "/" \
| awk '{print $2}' | sed 's/G//g' | while read line ; do x=($line + $x); done ; echo "($x) / 1024 / 1024 / 2" | bc

Get console idle time

echo $((`ioreg -c IOHIDSystem | sed -e '/HIDIdleTime/ !{ d' -e 't' -e '}' -e 's/.* = //g' -e 'q'` / 1000000000))

System Tuning

Any of these can be set manually with:

sudo sysctl -w sysctl.key=value

Place the following in /etc/sysctl.conf and reboot to boost your limits

# values increased by 2x over defaults
kern.maxfiles=24576
kern.maxfilesperproc=20480
kern.maxprocperuid=200
kern.maxproc=1064

debugging / hidden preferences

iChat Logging

defaults write com.apple.iChat Log YES
defaults write com.apple.iChat Log.SecureIM YES
defaults write com.apple.iChatAgent Log YES
defaults write com.apple.iChatAgent Log.SecureIM YES
/Applications/iChat.app/Contents/MacOS/iChat -errorLogLevel 7

Mail logging

/Applications/Mail.app/Contents/MacOS/Mail -LogActivityOnHost bar.company.com