一小段shell 不懂

benjiamsh

#!/bin/bash

buildtype=${1:-"release"}

pkgdir=packages

rm -rf $pkgdir
mkdir -p $pkgdir

build_arch=`dpkg --print-architecture`

changelogfile=debian/changelog
build_number=${BUILD_NUMBER:-0}
# update the changelog automatically
git-changelog.sh --auto -E 3 -n $build_number $changelogfile


buildtype=${1:-"release"} 这句什么意思

build_number=${BUILD_NUMBER:-0} 这句什么意思
求解释

yestreenstars

看十三问~

wshbnmxy

buildtype=${1:-"release"} 如果$1存在且不等于null，相当于buildtype=${1}，否则相当于buildtype="release"

build_number=${BUILD_NUMBER:-0}同理

expert1

man bash

Shell_HAT

http://bbs.chinaunix.net/viewthr ... p;page=6#pid1595135

zhleiling

${parameter:-word}
              Use  Default Values.  If parameter is unset or null, the expansion of word is substituted.  Otherwise, the value of parameter is substi-
              tuted.