linux - Add or update a configuration record in /etc/environment -

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my /etc/environment looks this:

cat /etc/environment path="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games"

i wish use command (sed, awk, python, whatever....) make 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 catch is, rather 1 liner (in fields of sed -xyz /domagic/ /etc/environment), needs contain merging logic - either appends new configuration record or update existing one. bottom line, should prevent file looking this: (caused 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 trick questions, because i'm trying avoid using custom scripts, such as

/usr/local/bin/propupdate /etc/environment java_home "/usr/lib/jvm/java-6-sun"

/usr/local/bin/propupdate following script (written sake of example, may contain bugs. comments appreciated)

#!/bin/bash  # append/update configuration record in 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} ]];   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}" ]];         echo "configuration file ${configuration_file} not exist" >&2         exit $e_badfile fi  if [[ ! -w "${configuration_file}" ]];         echo "can't modify ${configuration_file}" >&2         exit $e_badfile fi    ######################################### ## decide parameter adding ## ######################################### __param_found=0  # first check configuration_parameter supplied use contains "=" if [[ ${configuration_parameter} == *=* ]];         # should exist in file, plain         if grep -qe "^${configuration_parameter}" "${configuration_file}";                 __param_found=1                 suffix_regex='[[:space:]]*'         fi else         # ok, sophisticated user, did not send "=" parameter...         if grep -qe "^${configuration_parameter}[[:space:]]*=" "${configuration_file}";                 # let's check if such configuration parameter + "=" exists                 __param_found=1                 suffix_regex='[[:space:]]*=[[:space:]]*'         elif grep -qe "^${configuration_parameter}[[:space:]]+" "${configuration_file}";                 # if such parameter exists, @                 __param_found=1                 suffix_regex='[[:space:]]\+'         fi fi   if [[ $__param_found == 1 ]];         #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 [[ ${configuration_parameter} == *=* ]];                 # configuration parameter contains "=" in it's name, append                 echo "${configuration_parameter}${configuration_value}" >> "${configuration_file}"         else                 # try guess if file "param = value" or "param value" type of file.                 if grep -qe "^[[:alnum:]]+[[:space:]]*=" "${configuration_file}";                         # seems "param = value" type of file                         echo "${configuration_parameter}=${configuration_value}" >> "${configuration_file}"                 else                         # seems "param  value" type of file                         echo "${configuration_parameter} ${configuration_value}" >> "${configuration_file}"                 fi         fi fi  #cat $configuration_file

thank you, maxim.

-- update: kinda liked script, i've improved bit. seems production ready. enjoy.

instead of trying parse /etc/environment file, instead create file own name in /etc/profile.d/, described in my answer relevant question. copy on during installation, because contains content. let alone make scripts shorter.


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