Question

if [ "$#" -ne 1 ]; then
    flag=1;
elif ! [[ "$1" == "arg1" || "$1" == "arg2" || "$1" == "arg3" || ...... ]]; then 
    echo "Invalid"
    flag=1;
fi

if [ "$flag" == "1" ]; then
    echo "Usage of script...."
    exit
fi
count="$(ls *.mov | wc -l)"
if [[ "$count" -eq 0 ]] 
then
    echo there are 0 .mov files in this path
elif [[ "$count" -eq 1 ]] 
then
    echo there is 1 .mov file in this path
    vlc *.mov
elif [[ $1 = "arg1" ]] ; then
    echo entered the tough part....coz its not entering`enter code here`
elif [[ "$1" == "arg2" ]] || [[ "$1" == "arg10" ]] ; then
    echo entered here atleast...but not entering 
else
    script continues

代码不会输入涉及命令行参数的elif条件。尝试=，==， - eq，双方括号，单方括号。但它没有进入，请帮忙

Answer 1

you should add a disclaimer at the head of the script: " #!/bin/bash"

I tried your script and it does get into the elif. the code I used is:

if [ "$#" -ne 1 ]; then

echo "not 1 arg"

flag=1;

elif ! [[ "$1" == "arg1" || "$1" == "arg2" || "$1" == "arg3"  ]]; then

echo "Invalid"

flag=1;

else

echo "else"

fi

and the input/output are:

$ . script.sh 1 2

not 1 arg

$ . script.sh 1

Invalid

$ . script.sh arg1

else

I tried the second part and it is also working:

count=$2

if [[ "$count" -eq 0 ]] ;then

    echo "there are 0 .mov files in this path"

elif [[ "$count" -eq 1 ]] ;then

    echo "there is 1 .mov file in this path"

    vlc *.mov

elif [[ $1 = "arg1" ]] ; then

    echo "arg1 "

elif [[ "$1" == "arg2" ]] || [[ "$1" == "arg10" ]] ; then

    echo "arg2 or arg10 "

else

echo "else"

fi

and tested it (second argument is "count"): $ . script.sh arg1 0 there are 0 .mov files in this path $ . script.sh 1 0 there are 0 .mov files in this path $ . script.sh arg10 0 there are 0 .mov files in this path $ . script.sh arg1 1 there is 1 .mov file in this path The program 'vlc' is currently not installed. To run 'vlc' please ask your administrator to install the package 'vlc-nox' $ . script.sh arg10 1 there is 1 .mov file in this path The program 'vlc' is currently not installed. To run 'vlc' please ask your administrator to install the package 'vlc-nox' $ . script.sh 1 1 there is 1 .mov file in this path The program 'vlc' is currently not installed. To run 'vlc' please ask your administrator to install the package 'vlc-nox' $ . script.sh arg1 2 arg1 $ . script.sh 1 2 else $ . script.sh arg10 2 arg2 or arg10

Answer 2

You should look into the bash case statement http://mywiki.wooledge.org/BashGuide/TestsAndConditionals#Choices_.28case_and_select.29

For this particular script, it will make your script easier to read and your branching problem will most likely go away..

Answer 3

if your purpose is to handle the arguments passed to the script by command line it's better to use the getopts bash this is just an example that you can adapt to your scope:

#!/bin/bash
function usage {
  echo "usage: ..."
}

while getopts f:o:h opt; do
  case $opt in
    f)
      fileName=$OPTARG
      echo "filename[$fileName]"
      ;;
    o)
      otherargs=$OPTARG
      echo "otherargs[$otherargs]"
      ;;
    h)
      usage && exit 0
      ;;
    ?)
      usage && exit 2
      ;;
  esac
done
~

output

[myShell] ➤ ./n -h
usage: ...

[myShell] ➤ ./n -f myfilename
filename[myfilename]

[myShell] ➤ ./n -o other
otherargs[other]

[myShell] ➤ ./n -l
./n: illegal option -- l
usage: ...

为什么不进入arg1如果是condion，尽管arg1是命令行参数

3 个答案: