Grep entire directories

To find a phrase that could be found somewhere in the current directory, use the command:

grep -r -i searchString ./

For example:

grep -r -i splunk /etc

This would search the entire /etc filesystem for any line with the word "splunk" located therein. Another way to do this would be the command:

find / -type f -print | xargs grep splunk

It works well with HP-UX and other Unixes.

Tar with date and a twist of chocolate

Here is a way to tar up a set of important directories with the date. You can use this as a log archive, or with Splunk. This uses the highest compression of gzip (-9).

tar cp /myapp/logs /var/log/messages /var/log/httpd/ | gzip -9c > /tmp/oldlogs`date +"%Y%m%d"`.tgz

Reboot your computer after 4082.97902312 years

For some cool reason, the maximum time that the Linux shutdown command will accept is 2,147,483,647 minutes, which is 4082.97902312 years. If you think your hardware is going to last that long, execute the command:

#shutdown -r -F 2147483647

In a little over 4,000 years, it will reboot and check your disks. Hopefully by then you will be doing something cooler than counting down, like golfing on Mars.

A quality PostgreSQL startup script

I have went through several iterations of PostgreSQL startup scripts. Most are less than useful. This one, modified for my use (changed some of the directory structure, and tailored for Postgres 8.3.6) is originally provided by the Postgres YUM repository, and is actually useful. This is in stark comparison to the quasi-useful one that is included in the source package in file postgresql-version/contrib/start-scripts/linux This is designed for Red Hat iterations of Linux, but may with small modifications, work with Debian, Ubuntu, and SuSE. Enjoy.


#!/bin/sh
# postgresql This is the init script for starting up the PostgreSQL
# server
#
# chkconfig: - 64 36
# description: Starts and stops the PostgreSQL backend daemon that handles \
# all database requests.
# processname: postmaster
# pidfile: /var/run/postmaster.pid
PGVERSION=8.3.6
# PGMAJORVERSION is major version, e.g., 8.0 (this should match PG_VERSION)
PGMAJORVERSION=`echo "$PGVERSION" | sed 's/^\([0-9]*\.[0-9]*\).*$/\1/'`

# Source function library.
INITD=/etc/rc.d/init.d
. $INITD/functions

# Get function listing for cross-distribution logic.
TYPESET=`typeset -f|grep "declare"`

# Get config.
. /etc/sysconfig/network

# Find the name of the script
NAME=`basename $0`
if [ ${NAME:0:1} = "S" -o ${NAME:0:1} = "K" ]
then
NAME=${NAME:3}
fi

# For SELinux we need to use 'runuser' not 'su'
if [ -x /sbin/runuser ]
then
SU=runuser
else
SU=su
fi


# Set defaults for configuration variables
PGENGINE=/app/pgsql/bin
PGPORT=5432
PGDATA=/app/pgsql/data

if [ -f "$PGDATA/PG_VERSION" ] && [ -d "$PGDATA/base/template1" ]
then
echo "Using old-style directory structure"
else
PGDATA=/app/pgsql/data
fi
PGLOG=/app/pgsql/data/pgstartup.log

# Override defaults from /etc/sysconfig/pgsql if file is present
[ -f /etc/sysconfig/pgsql/${NAME} ] && . /etc/sysconfig/pgsql/${NAME}

export PGDATA
export PGPORT

# Check that networking is up.
# Pretty much need it for postmaster.
[ "${NETWORKING}" = "no" ] && exit 0

[ -f "$PGENGINE/postmaster" ] || exit 1

script_result=0

start(){
PSQL_START=$"Starting ${NAME} service: "

# Make sure startup-time log file is valid
if [ ! -e "$PGLOG" -a ! -h "$PGLOG" ]
then
touch "$PGLOG" || exit 1
chown postgres:postgres "$PGLOG"
chmod go-rwx "$PGLOG"
[ -x /usr/bin/chcon ] && /usr/bin/chcon -u system_u -r object_r -t postgresql_log_t "$PGLOG" 2>/dev/null
fi

# Check for the PGDATA structure
if [ -f "$PGDATA/PG_VERSION" ] && [ -d "$PGDATA/base" ]
then
# Check version of existing PGDATA

if [ x`cat "$PGDATA/PG_VERSION"` != x"$PGMAJORVERSION" ]
then
SYSDOCDIR="(Your System's documentation directory)"
if [ -d "/usr/doc/postgresql-$PGVERSION" ]
then
SYSDOCDIR=/usr/doc
fi
if [ -d "/usr/share/doc/postgresql-$PGVERSION" ]
then
SYSDOCDIR=/usr/share/doc
fi
if [ -d "/usr/doc/packages/postgresql-$PGVERSION" ]
then
SYSDOCDIR=/usr/doc/packages
fi
if [ -d "/usr/share/doc/packages/postgresql-$PGVERSION" ]
then
SYSDOCDIR=/usr/share/doc/packages
fi
echo
echo $"An old version of the database format was found."
echo $"You need to upgrade the data format before using PostgreSQL."
echo $"See $SYSDOCDIR/postgresql-$PGVERSION/README.rpm-dist for more information."
exit 1
fi

# No existing PGDATA! Warn the user to initdb it.
else
echo
echo "$PGDATA is missing. Use \"service postgresql initdb\" to initialize the cluster first."
echo_failure
echo
exit 1
fi

echo -n "$PSQL_START"
$SU -l postgres -c "$PGENGINE/postmaster -p '$PGPORT' -D '$PGDATA' ${PGOPTS} &" >> "$PGLOG" 2>&1 < /dev/null
sleep 2
pid=`pidof -s "$PGENGINE/postmaster"`
if [ $pid ] && [ -f "$PGDATA/postmaster.pid" ]
then
success "$PSQL_START"
touch /var/lock/subsys/${NAME}
head -n 1 "$PGDATA/postmaster.pid" > "/var/run/postmaster.${PGPORT}.pid"
echo
else
failure "$PSQL_START"
echo
script_result=1
fi
}

stop(){
echo -n $"Stopping ${NAME} service: "
$SU -l postgres -c "$PGENGINE/pg_ctl stop -D '$PGDATA' -s -m fast" > /dev/null 2>&1 < /dev/null
ret=$?
if [ $ret -eq 0 ]
then
echo_success
else
echo_failure
script_result=1
fi
echo
rm -f "/var/run/postmaster.${PGPORT}.pid"
rm -f "/var/lock/subsys/${NAME}"
}

restart(){
stop
start
}

initdb(){
if [ -f "$PGDATA/PG_VERSION" ]
then
echo "Data directory is not empty!"
echo_failure
else
echo -n $"Initializing database: "
if [ ! -e "$PGDATA" -a ! -h "$PGDATA" ]
then
mkdir -p "$PGDATA" || exit 1
chown postgres:postgres "$PGDATA"
chmod go-rwx "$PGDATA"
fi
# Clean up SELinux tagging for PGDATA
[ -x /sbin/restorecon ] && /sbin/restorecon "$PGDATA"
# Initialize the database
$SU -l postgres -c "$PGENGINE/initdb --pgdata='$PGDATA' --auth='ident sameuser'" >> "$PGLOG" 2>&1 < /dev/null
# Create directory for postmaster log
mkdir "$PGDATA/pg_log"
chown postgres:postgres "$PGDATA/pg_log"
chmod go-rwx "$PGDATA/pg_log"

[ -f "$PGDATA/PG_VERSION" ] && echo_success
[ ! -f "$PGDATA/PG_VERSION" ] && echo_failure
echo
fi
}
condrestart(){
[ -e /var/lock/subsys/${NAME} ] && restart
}

condstop(){
[ -e /var/lock/subsys/${NAME} ] && stop
}

reload(){
$SU -l postgres -c "$PGENGINE/pg_ctl reload -D '$PGDATA' -s" > /dev/null 2>&1 < /dev/null
}

# This script is slightly unusual in that the name of the daemon (postmaster)
# is not the same as the name of the subsystem (postgresql)

# See how we were called.
case "$1" in
start)
start
;;
stop)
stop
;;
status)
status -p /var/run/postmaster.${PGPORT}.pid
script_result=$?
;;
restart)
restart
;;
initdb)
initdb
;;
condrestart)
condrestart
;;
condstop)
condstop
;;
reload|force-reload)
reload
;;
*)
echo $"Usage: $0 {start|stop|status|restart|condrestart|condstop|reload|force-reload|initdb}"
exit 1
esac

exit $script_result