一般來說編譯一個sdk或者一個比較大的工程項目，第一步都是執行 envsetup.sh這個腳本，比如編譯android，qt源碼以及其他一些嵌入式的sdk。
而且執行的時候需要特別注意使用
source build/envsetup.sh
或者
. ./build/envsetup.sh
特別注意兩個點之間是有空格的，這個作用相當於source。
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一般執行shell腳本時直接用./來執行，此時是系統啟動一個子shell進程來執行命令，執行完后返回最后一條指令的結果（可以用echo $?來獲取執行結果值（0-255）），其結果並不會對當前的BASH產生影響。
source命令的用法：
source FileName
他的作用是在當前bash環境下讀取並執行FileName中的指令，這個命令執行完之后會把FileName執行過程中的一些輸出設置到當前的BASH中，也就設置環境變量。
需要注意的是用source執行新產生的這些變量的作用范圍（作用域）只是在當前終端有用，如果你關閉當前終端了，或者在其他終端是無法使用這些新增的變量的。
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當我們用source命令執行完encsetup.sh的時候，里面設置的一些變量（方法）就會輸出到當前的BASH環境中，在后續的過程中我們就可以在當前終端使用這些變量，比如用android的envsetup.sh來說，執行完后會增加一些shell cmd及環境變量可以使用
輸入hmm可以看到以下幫助信息
Invoke ". build/envsetup.sh" from your shell to add the following functions to your environment:
- lunch: lunch <product_name>-<build_variant>
- tapas: tapas [<App1> <App2> ...] [arm|x86|mips|armv5] [eng|userdebug|user] - croot: Changes directory to the top of the tree. - m: Makes from the top of the tree. - mm: Builds all of the modules in the current directory, but not their dependencies. - mmm: Builds all of the modules in the supplied directories, but not their dependencies. - mma: Builds all of the modules in the current directory, and their dependencies. - mmma: Builds all of the modules in the supplied directories, and their dependencies. - cgrep: Greps on all local C/C++ files. - jgrep: Greps on all local Java files. - resgrep: Greps on all local res/*.xml files. - godir: Go to the directory containing a file. Look at the source to view more functions. The complete list is: addcompletions add_lunch_combo cgrep check_product check_variant choosecombo chooseproduct choosetype choosevariant cproj croot findmakefile gdbclient gdbwrapper get_abs_build_var getbugreports get_build_var getlastscreenshot getprebuilt getscreenshotpath getsdcardpath gettargetarch gettop godir hmm isviewserverstarted jgrep key_back key_home key_menu lunch _lunch m mangrep mm mma mmm mmma pez pid printconfig print_lunch_menu qpid resgrep runhat runtest sepgrep set_java_home setpaths set_sequence_number set_stuff_for_environment settitle smoketest stacks startviewserver stopviewserver systemstack tapas tracedmdump
liuxueneng@airfly-dev:~/workCode/allwinner_h2_2018-0907/android$ source build/envsetup.sh find Makefile including device/generic/mips/vendorsetup.sh including device/generic/armv7-a-neon/vendorsetup.sh including device/generic/x86/vendorsetup.sh including device/softwinner/common/vendorsetup.sh including device/softwinner/dolphin-fvd-p1/vendorsetup.sh liuxueneng@airfly-dev:~/workCode/allwinner_h2_2018-0907/android$ hmm Invoke ". build/envsetup.sh" from your shell to add the following functions to your environment: - lunch: lunch <product_name>-<build_variant> - tapas: tapas [<App1> <App2> ...] [arm|x86|mips|armv5] [eng|userdebug|user] - croot: Changes directory to the top of the tree. - m: Makes from the top of the tree. - mm: Builds all of the modules in the current directory, but not their dependencies. - mmm: Builds all of the modules in the supplied directories, but not their dependencies. - mma: Builds all of the modules in the current directory, and their dependencies. - mmma: Builds all of the modules in the supplied directories, and their dependencies. - cgrep: Greps on all local C/C++ files. - jgrep: Greps on all local Java files. - resgrep: Greps on all local res/*.xml files. - godir: Go to the directory containing a file. Look at the source to view more functions. The complete list is: addcompletions add_lunch_combo cgrep check_product check_variant choosecombo chooseproduct choosetype choosevariant cproj croot findmakefile gdbclient gdbwrapper get_abs_build_var getbugreports get_build_var getlastscreenshot getprebuilt getscreenshotpath getsdcardpath gettargetarch gettop godir hmm isviewserverstarted jgrep key_back key_home key_menu lunch _lunch m mangrep mm mma mmm mmma pez pid printconfig print_lunch_menu qpid resgrep runhat runtest sepgrep set_java_home setpaths set_sequence_number set_stuff_for_environment settitle smoketest stacks startviewserver stopviewserver systemstack tapas tracedmdump liuxueneng@airfly-dev:~/workCode/allwinner_h2_2018-0907/android$
這些命令都是在android/build/envsetup.sh中定義輸出的，可以打開看下
export ROOT_DIR=${PWD} MAKEFILE=$ROOT_DIR/Makefile if [ -f $MAKEFILE ]; then echo "find Makefile" else echo "copy Makefile" cp $ROOT_DIR/build/core/root.mk $ROOT_DIR/Makefile fi function hmm() { cat <<EOF Invoke ". build/envsetup.sh" from your shell to add the following functions to your environment: - lunch: lunch <product_name>-<build_variant> - tapas: tapas [<App1> <App2> ...] [arm|x86|mips|armv5] [eng|userdebug|user] - croot: Changes directory to the top of the tree. - m: Makes from the top of the tree. - mm: Builds all of the modules in the current directory, but not their dependencies. - mmm: Builds all of the modules in the supplied directories, but not their dependencies. - mma: Builds all of the modules in the current directory, and their dependencies. - mmma: Builds all of the modules in the supplied directories, and their dependencies. - cgrep: Greps on all local C/C++ files. - jgrep: Greps on all local Java files. - resgrep: Greps on all local res/*.xml files. - godir: Go to the directory containing a file. Look at the source to view more functions. The complete list is: EOF T=$(gettop) local A A="" for i in `cat $T/build/envsetup.sh | sed -n "/^function /s/function \([a-z_]*\).*/\1/p" | sort`; do A="$A $i" done echo $A } # Get the value of a build variable as an absolute path. function get_abs_build_var() { T=$(gettop) if [ ! "$T" ]; then echo "Couldn't locate the top of the tree. Try setting TOP." >&2 return fi (\cd $T; CALLED_FROM_SETUP=true BUILD_SYSTEM=build/core \ make --no-print-directory -C "$T" -f build/core/config.mk dumpvar-abs-$1) }
這些方法還有一些變量都會輸出到當前的BASH環境中，輸入env指令就可以打印出當前BASH下的所有環境變量
liuxueneng@airfly-dev:~/workCode/allwinner_h2_2018-0907/android$ env XDG_SESSION_ID=13509 TERM=xterm SHELL=/bin/bash SSH_CLIENT=192.168.11.102 1097 22 OLDPWD=/home/liuxueneng SSH_TTY=/dev/pts/26 USER=liuxueneng LS_COLORS=rs=0:di=01;34:ln=01;36:mh=00:pi=40;33:so=01;35:do=01;35:bd=40;33;01:cd=40;33;01:or=40;31;01:mi=00:su=37;41:sg=30;43:ca=30;41:tw=30;42:ow=34;42:st=37;44:ex=01;32:*.tar=01;31:*.tgz=01;31:*.arc=01;31:*.arj=01;31:*.taz=01;31:*.lha=01;31:*.lz4=01;31:*.lzh=01;31:*.lzma=01;31:*.tlz=01;31:*.txz=01;31:*.tzo=01;31:*.t7z=01;31:*.zip=01;31:*.z=01;31:*.Z=01;31:*.dz=01;31:*.gz=01;31:*.lrz=01;31:*.lz=01;31:*.lzo=01;31:*.xz=01;31:*.bz2=01;31:*.bz=01;31:*.tbz=01;31:*.tbz2=01;31:*.tz=01;31:*.deb=01;31:*.rpm=01;31:*.jar=01;31:*.war=01;31:*.ear=01;31:*.sar=01;31:*.rar=01;31:*.alz=01;31:*.ace=01;31:*.zoo=01;31:*.cpio=01;31:*.7z=01;31:*.rz=01;31:*.cab=01;31:*.jpg=01;35:*.jpeg=01;35:*.gif=01;35:*.bmp=01;35:*.pbm=01;35:*.pgm=01;35:*.ppm=01;35:*.tga=01;35:*.xbm=01;35:*.xpm=01;35:*.tif=01;35:*.tiff=01;35:*.png=01;35:*.svg=01;35:*.svgz=01;35:*.mng=01;35:*.pcx=01;35:*.mov=01;35:*.mpg=01;35:*.mpeg=01;35:*.m2v=01;35:*.mkv=01;35:*.webm=01;35:*.ogm=01;35:*.mp4=01;35:*.m4v=01;35:*.mp4v=01;35:*.vob=01;35:*.qt=01;35:*.nuv=01;35:*.wmv=01;35:*.asf=01;35:*.rm=01;35:*.rmvb=01;35:*.flc=01;35:*.avi=01;35:*.fli=01;35:*.flv=01;35:*.gl=01;35:*.dl=01;35:*.xcf=01;35:*.xwd=01;35:*.yuv=01;35:*.cgm=01;35:*.emf=01;35:*.ogv=01;35:*.ogx=01;35:*.aac=00;36:*.au=00;36:*.flac=00;36:*.m4a=00;36:*.mid=00;36:*.midi=00;36:*.mka=00;36:*.mp3=00;36:*.mpc=00;36:*.ogg=00;36:*.ra=00;36:*.wav=00;36:*.oga=00;36:*.opus=00;36:*.spx=00;36:*.xspf=00;36: ROOT_DIR=/home/liuxueneng/workCode/allwinner_h2_2018-0907/android MAIL=/var/mail/liuxueneng PATH=/home/liuxueneng/bin:/home/liuxueneng/.local/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/snap/bin PWD=/home/liuxueneng/workCode/allwinner_h2_2018-0907/android LANG=en_HK.UTF-8 SHLVL=1 HOME=/home/liuxueneng LANGUAGE=en_HK:en LOGNAME=liuxueneng XDG_DATA_DIRS=/usr/local/share:/usr/share:/var/lib/snapd/desktop SSH_CONNECTION=192.168.11.102 1097 192.168.11.111 22 LESSOPEN=| /usr/bin/lesspipe %s XDG_RUNTIME_DIR=/run/user/1006 LESSCLOSE=/usr/bin/lesspipe %s %s _=/usr/bin/env
其中我們可以看到至少以下兩個變量是執行剛才的envsetup.sh輸出來的
ROOT_DIR=/home/liuxueneng/workCode/allwinner_h2_2018-0907/android
聯系以上的的croot指令就是改變當前工作目錄的哦ROOT_DIR中。
另外還可以查看輸出到當前BASH環境中的臨時shell方法，輸入set指令來查看（小心會有一大堆東西噴出來）
tracedmdump () { T=$(gettop); if [ ! "$T" ]; then echo "Couldn't locate the top of the tree. Try setting TOP."; return; fi; local prebuiltdir=$(getprebuilt); local arch=$(gettargetarch); local KERNEL=$T/prebuilts/qemu-kernel/$arch/vmlinux-qemu; local TRACE=$1; if [ ! "$TRACE" ]; then echo "usage: tracedmdump tracename"; return; fi; if [ ! -r "$KERNEL" ]; then echo "Error: cannot find kernel: '$KERNEL'"; return; fi; local BASETRACE=$(basename $TRACE); if [ "$BASETRACE" = "$TRACE" ]; then TRACE=$ANDROID_PRODUCT_OUT/traces/$TRACE; fi; echo "post-processing traces..."; rm -f $TRACE/qtrace.dexlist; post_trace $TRACE; if [ $? -ne 0 ]; then echo "***"; echo "*** Error: malformed trace. Did you remember to exit the emulator?"; echo "***"; return; fi; echo "generating dexlist output..."; /bin/ls $ANDROID_PRODUCT_OUT/system/framework/*.jar $ANDROID_PRODUCT_OUT/system/app/*.apk $ANDROID_PRODUCT_OUT/data/app/*.apk 2> /dev/null | xargs dexlist > $TRACE/qtrace.dexlist; echo "generating dmtrace data..."; q2dm -r $ANDROID_PRODUCT_OUT/symbols $TRACE $KERNEL $TRACE/dmtrace || return; echo "generating html file..."; dmtracedump -h $TRACE/dmtrace >| $TRACE/dmtrace.html || return; echo "done, see $TRACE/dmtrace.html for details"; echo "or run:"; echo " traceview $TRACE/dmtrace" } treegrep () { find . -name .repo -prune -o -name .git -prune -o -regextype posix-egrep -iregex '.*\.(c|h|cpp|S|java|xml)' -type f -print0 | xargs -0 grep --color -n -i "$@" } verity_file_init () { echo "verity_file_init"; cp -rf $DEVICE/verity ${OUT}; $DEVICE/verity/gen_file_verify_block.sh ${OUT}/system; cp -f ${OUT}/verity/verity_block ${OUT}/verity_block.img } verity_key_init () { $DEVICE/verity/gen_dm_verity_key.sh; cp -f $DEVICE/verity/rsa_key/verity_key $OUT/root }
以上treegrep tracedmdump等shell方法都是從envsetup.sh輸出來的。
后續講解下輸出的m mm mmm mmma croot cgrep 等作用及用法。