My /etc/environment looks like this:
cat /etc/environment
PATH="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games"
I wish to use a command (sed, awk, python, whatever....) that will make it look like this:
cat /etc/environment
PATH="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games"
JAVA_HOME="/usr/lib/jvm/java-6-sun"
Now the catch is, I would rather it be a 1 liner (in the fields of sed -XYZ /DoMagic/ /etc/environment), it needs to contain merging logic that is - either appends a new configuration record or update an existing one. Bottom line, it should prevent the file from looking like this: (Caused by in experienced shell scripters calling echo >> on each invocation)
cat /etc/environment
PATH="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games"
JAVA_HOME="/usr/lib/jvm/java-5-sun"
JAVA_HOME="/usr/lib/jvm/java-6-sun"
JAVA_HOME="/usr/lib/jvm/java-6-sun"
JAVA_HOME="/usr/lib/jvm/java-6-sun"
I guess this is a trick questions, because what I'm trying to avoid using custom scripts, such as
/usr/local/bin/PropUpdate /etc/environment JAVA_HOME "/usr/lib/jvm/java-6-sun"
/usr/local/bin/PropUpdate is the following script (written for the sake of example, may contain bugs. Comments are appreciated)
#!/bin/bash
# Append/Update a configuration record in a file
#
# Usage example:
# /usr/local/bin/PropUpdate /etc/environment JAVA_HOME "/usr/lib/jvm/java-6-sun"
#
# Author Maxim Veksler <maxim@vekslers.org>
# Version 0.5-2010-07-27
EXPECTED_ARGS=3
E_BADARGS=3
E_BADFILE=4
if [[ $# -ne ${EXPECTED_ARGS} ]]; then
echo "Usage: `basename $0` /path/to/config.conf ParameterName newValueText" >&2
exit $E_BADARGS
fi
CONFIGURATION_FILE="$1"
CONFIGURATION_PARAMETER="$2"
CONFIGURATION_VALUE="$3"
if [[ ! -e "${CONFIGURATION_FILE}" ]]; then
echo "Configuration file ${CONFIGURATION_FILE} does not exist" >&2
exit $E_BADFILE
fi
if [[ ! -w "${CONFIGURATION_FILE}" ]]; then
echo "Can't modify ${CONFIGURATION_FILE}" >&2
exit $E_BADFILE
fi
#########################################
## Decide what parameter we are adding ##
#########################################
__param_found=0
# First check CONFIGURATION_PARAMETER supplied by use that contains "="
if [[ ${CONFIGURATION_PARAMETER} == *=* ]]; then
# It should exist in the file, plain
if grep -qE "^${CONFIGURATION_PARAMETER}" "${CONFIGURATION_FILE}"; then
__param_found=1
SUFFIX_REGEX='[[:space:]]*'
fi
else
# OK, sophisticated user, did not send "=" with the parameter...
if grep -qE "^${CONFIGURATION_PARAMETER}[[:space:]]*=" "${CONFIGURATION_FILE}"; then
# Let's check if such configuration with Parameter + "=" exists
__param_found=1
SUFFIX_REGEX='[[:space:]]*=[[:space:]]*'
elif grep -qE "^${CONFIGURATION_PARAMETER}[[:space:]]+" "${CONFIGURATION_FILE}"; then
# If such parameter exists, at all
__param_found=1
SUFFIX_REGEX='[[:space:]]\+'
fi
fi
if [[ $__param_found == 1 ]]; then
#echo sed -i "s|^\(${CONFIGURATION_PARAMETER}${SUFFIX_REGEX}\).*$|\1${CONFIGURATION_VALUE}|g" "${CONFIGURATION_FILE}"
sed -i "s|^\(${CONFIGURATION_PARAMETER}${SUFFIX_REGEX}\).*$|\1${CONFIGURATION_VALUE}|g" "${CONFIGURATION_FILE}"
else
if [[ ${CONFIGURATION_PARAMETER} == *=* ]]; then
# Configuration parameter contains "=" in it's name, good just append
echo "${CONFIGURATION_PARAMETER}${CONFIGURATION_VALUE}" >> "${CONFIGURATION_FILE}"
else
# Try to guess if this file is a "param = value" or "param value" type of file.
if grep -qE "^[[:alnum:]]+[[:space:]]*=" "${CONFIGURATION_FILE}"; then
# Seems like a "param = value" type of file
echo "${CONFIGURATION_PARAMETER}=${CONFIGURATION_VALUE}" >> "${CONFIGURATION_FILE}"
else
# Seems like a "param value" type of file
echo "${CONFIGURATION_PARAMETER} ${CONFIGURATION_VALUE}" >> "${CONFIGURATION_FILE}"
fi
fi
fi
#cat $CONFIGURATION_FILE
Thank you, Maxim.
-- Update: I actually kinda liked this script, so I've improved it a bit. It now seems to be production ready. Enjoy.
