shell example01

条件判断

if [[ -e ${1} ]]; then
  echo "$(tput setaf 2) found ${1} $(tput sgr0)"
  cat ${1}
else
  echo "$(tput setaf 1) not found ${1} $(tput sgr0)"
  exit 1
fi

//简化
 [[ -e ${1} && -e ${2} ]] && cat ${1} > ${2}

//判断取反

txt='4.txt'

if ! [[ -e ${txt} ]]; then
  touch ${txt}
  echo "touch ${txt}; name length ${#txt}"
fi

//多重选择

bold=$(tput bold)
underline=$(tput smul)
normal=$(tput sgr0)
red=$(tput setaf 1)
green=$(tput setaf 2)

if [[ -e 'a1.txt' ]]; then
  echo "${bold}${underline}${green} search a{1..5}.txt ${normal}"
  ls a{1..5}.txt 2> log.txt
elif [[ -e 'b1.txt' ]]; then
  echo "${bold}${underline}${green} search b{1..5}.txt ${normal}"
  ls b{1..5} txt 2>> log.txt
else
  echo "${bold}${underline}${red} create a{1..4}.txt ${normal}"
  touch a{1..5}.txt
fi

显示时间

//查找文件
start=$(date +%s)
echo 'start search'

find ~/ -name '*.txt' &> log.txt

echo 'end search'

end=$(date +%s)         //%s以秒为单位
difference=$(( end - start))
echo "Time is ${difference} seconds".

//显示具体的执行时间
echo 'start search'
time find ~/ -type f -name '*txt' &> log.txt     //仅仅是文件
echo 'end search'

//计时器
echo '- Count Start'
tput sc    //存储光标位置
count=0

while [[ ${count} -lt 20 ]]
do
  let count++
  sleep 1      //延迟一秒
  tput rc      //恢复光标位置
  tput ed     //清除从当前光标位置到行尾之间的所有内容
  echo "- ${count}"
done

echo "- Count End"

循环

//循环创建文件
for i in file{1..9}.txt
do
  if [[ -e ${i} ]]
  then
    echo "find ${i} skip"
  else
    echo "start create ${i}"
    touch ${i}
fi
done
echo "finished"

//判断空文件
files=$(echo *.txt)
normal=$(tput sgr0)
type="%-10s %-8s\n"

printf "$(tput bold)${type}" name blank
printf ${normal}
for file in ${files}; do
  check=true
  color=$(tput setaf 1)
  test -s ${file}  && check=false color=$(tput setaf 2)
  printf "${color}${type}" ${file} ${check}
  printf ${normal}
done

简单编辑

//去除空白
cat $1 | sed '/s //g' > new.log             //sed 's/要被取代的字串/新的字串/g'   

//对特定格式的文档计算重复值
//log.txt
account1:passwd1
account2:passwd2
account3:passwd3
account2:passwd4
account4:passwd5
account6:passwd6
account1:passwd7

//
awk -F: 'x[$1]++ {print $1 " is duplicated"}'  log.txt           //awk -F 指定分割字符