java 环境变量设置

假设jdk 安装目录 /usr/local/jdk1.7.0_80

[pso@localhost ~]$ cd /etc/
[pso@localhost etc]$ vi profile

# /etc/profile

# System wide environment and startup programs, for login setup
# Functions and aliases go in /etc/bashrc

# It's NOT a good idea to change this file unless you know what you
# are doing. It's much better to create a custom.sh shell script in
# /etc/profile.d/ to make custom changes to your environment, as this
# will prevent the need for merging in future updates.

pathmunge () {
case ":${PATH}:" in
*:"$1":*)
;;
*)
if [ "$2" = "after" ] ; then
PATH=$PATH:$1
else
PATH=$1:$PATH
fi
esac
}

if [ -x /usr/bin/id ]; then
if [ -z "$EUID" ]; then
# ksh workaround
EUID=`id -u`
UID=`id -ru`
fi
USER="`id -un`"
LOGNAME=$USER
MAIL="/var/spool/mail/$USER"
fi

# Path manipulation
if [ "$EUID" = "0" ]; then
pathmunge /sbin
pathmunge /usr/sbin
pathmunge /usr/local/sbin
else
pathmunge /usr/local/sbin after
pathmunge /usr/sbin after
pathmunge /sbin after
fi

TMOUT=1800
HISTTIMEFORMAT="%F %T "
if [ "$HISTCONTROL" = "ignorespace" ] ; then
export HISTCONTROL=ignoreboth
else
export HISTCONTROL=ignoredups
fi

export PATH USER LOGNAME MAIL HOSTNAME HISTSIZE HISTCONTROL

# By default, we want umask to get set. This sets it for login shell
# Current threshold for system reserved uid/gids is 200
# You could check uidgid reservation validity in
# /usr/share/doc/setup-*/uidgid file
if [ $UID -gt 199 ] && [ "`id -gn`" = "`id -un`" ]; then
umask 002
else
umask 022
fi

for i in /etc/profile.d/*.sh ; do
if [ -r "$i" ]; then
if [ "${-#*i}" != "$-" ]; then
. "$i"
else
. "$i" >/dev/null 2>&1
fi
fi
done

unset i
unset -f pathmunge
export HISTORY_FILE=/var/log/useraudit.log
export PROMPT_COMMAND='{ h=`history 1`;w=`who am i`;echo -e $(date "+%Y-%m-%d %H:%M:%S") -
-- $w ---$h;} >> $HISTORY_FILE'
JAVA_HOME=/usr/local/jdk1.7.0_80
PATH=$JAVA_HOME/bin:$PATH
export JAVA_HOME
export PATH

修改完文件后，需要执行source命令，将设置在文件中的配置信息马上生效

source ect/profile

---------------------------------------

source命令：

source命令也称为“点命令”，也就是一个点符号（.）。source命令通常用于重新执行刚修改的初始化文件，使之立即生效，而不必注销并重新登录。

用法： 

source filename 或 . filename

source命令除了上述的用途之外，还有一个另外一个用途。

在对编译系统核心时常常需要输入一长串的命令，如：

make mrproper

make menuconfig

make dep

make clean

make bzImage

…………

如果把这些命令做成一个文件，让它自动顺序执行，用source命令就可以做到--把一个文件的内容当成shell来执行，

先建立一个文件make_command（如/usr/src/linux-2.4.20），在其中输入一下内容：

make mrproper &&

make menuconfig &&

make dep &&

make clean &&

make bzImage

文件建立好之后，每次编译的时候，只需要在/usr/src/linux-2.4.20下输入：

source make_command

顺便补充一点，&&命令表示顺序执行由它连接的命令，但是只有它之前的命令成功执行完成了之后才可以继续执行它后面的命令。