pg_dump -d prod_db -U prod_db -h localhost > /tmp/transferdump.sql

psql -U prod_db_user -h localhost -t -d other_db -c "SELECT 'DROP TABLE ' || n.nspname || '.' ||
c.relname || ' CASCADE;' FROM pg_catalog.pg_class AS c LEFT JOIN
pg_catalog.pg_namespace AS n ON n.oid = c.relnamespace WHERE relkind =
'r' AND n.nspname NOT IN ('pg_catalog', 'pg_toast') AND
pg_catalog.pg_table_is_visible(c.oid)" >/tmp/dropothertables.sql;

psql -d other_db -h localhost -U other_db_user < /tmp/dropothertables.sql;
psql -d other_db -h localhost -U other_db_user < /tmp/transferdump.sql

bash

1

Make copy and transfer entire PostgreSQL DB

pg_dump -d prod_db -U prod_db -h localhost > /tmp/transferdump.sql

psql -U prod_db_user -h localhost -t -d other_db -c "SELECT 'DROP TABLE ' || n.nspname || '.' ||
c.relname || ' CASCADE;' FROM pg_catalog.pg_class AS c LEFT JOIN
pg_catalog.pg_namespace AS n ON n.oid = c.relnamespace WHERE relkind =
'r' AND n.nspname NOT IN ('pg_catalog', 'pg_toast') AND
pg_catalog.pg_table_is_visible(c.oid)" >/tmp/dropothertables.sql;

psql -d other_db -h localhost -U other_db_user < /tmp/dropothertables.sql;
psql -d other_db -h localhost -U other_db_user < /tmp/transferdump.sql

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• bash, 
• pgdump, 
• postgresql

# In .bashrc or .bash_profile
export HISTCONTROL=ignoredups:ignorespace
export HISTSIZE=10000
export HISTFILESIZE=1000000
export HISTTIMEFORMAT="%F %T "
export PROMPT_COMMAND='history -a'

bash

1

Bash—please save my history for ever and eternity (or, at least a really long time)

# In .bashrc or .bash_profile
export HISTCONTROL=ignoredups:ignorespace
export HISTSIZE=10000
export HISTFILESIZE=1000000
export HISTTIMEFORMAT="%F %T "
export PROMPT_COMMAND='history -a'

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• bash, 
• history

vim /etc/hostname
vim /etc/hosts
hostname new-hostname

bash

1

Change Linux hostname without reboot

vim /etc/hostname
vim /etc/hosts
hostname new-hostname

copy | embed

• admin, 
• bash, 
• linux

psql -t -d my_dbname -c "SELECT 'DROP TABLE ' || n.nspname || '.' ||
c.relname || ' CASCADE;' FROM pg_catalog.pg_class AS c LEFT JOIN
pg_catalog.pg_namespace AS n ON n.oid = c.relnamespace WHERE relkind =
'r' AND n.nspname NOT IN ('pg_catalog', 'pg_toast') AND
pg_catalog.pg_table_is_visible(c.oid)" >/tmp/droptables

psql -d my_dbname -f /tmp/droptables

bash

1

Drop all tables from PostgreSQL DB without superuser

psql -t -d my_dbname -c "SELECT 'DROP TABLE ' || n.nspname || '.' ||
c.relname || ' CASCADE;' FROM pg_catalog.pg_class AS c LEFT JOIN
pg_catalog.pg_namespace AS n ON n.oid = c.relnamespace WHERE relkind =
'r' AND n.nspname NOT IN ('pg_catalog', 'pg_toast') AND
pg_catalog.pg_table_is_visible(c.oid)" >/tmp/droptables

psql -d my_dbname -f /tmp/droptables

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• bash, 
• db, 
• postgresql

# Hold Command-S to boot into single-user mode

# Leopard - OOB reset
mount -uw /
rm /var/db/.AppleSetupDone
reboot

# Leopard - delete user
mount -uw /
rm /var/db/dslocal/nodes/Default/users/<shortname>.plist
rm -r /Users/<shortname>
halt

# Tiger - delete user and OOB reset
mount -uw /
rm -rf /Users/<shortname>
rm -rf /var/db/netinfo/local.nidb
rm -rf /var/db/.AppleSetupDone

bash

1

Hack a Mac, get an admin account

# Hold Command-S to boot into single-user mode

# Leopard - OOB reset
mount -uw /
rm /var/db/.AppleSetupDone
reboot

# Leopard - delete user
mount -uw /
rm /var/db/dslocal/nodes/Default/users/<shortname>.plist
rm -r /Users/<shortname>
halt

# Tiger - delete user and OOB reset
mount -uw /
rm -rf /Users/<shortname>
rm -rf /var/db/netinfo/local.nidb
rm -rf /var/db/.AppleSetupDone

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• admin, 
• bash, 
• mac, 
• oob, 
• password