Bash 脚本使用 #1 和 #2 参数，但如果找不到文件，则恢复为从用户读取

Question

因此，如果我的用户输入 bash copy.sh copysource.txt copydest.txt - 并且文件有效，我希望 copysource 附加到 copydest，然后通过 cat 显示文件

-如果文件名不正确或找不到...我希望提示用户在下面编码

#!/bin/bash
#Date: July 14 2016

if [ "$1" == "copysource.txt" ] && [ "$2" == "copydest.txt ]; then

cp $1 $2
echo "copies $1 to $2"
echo "contents of $2 are: "
cat $2

fi
#if the above was correct I want to script to stop
#otherwise if the info above was incorrect re: file names I want to user to be
#prompted to below code


clear
echo -n "Enter the source file name: "
read sourc


if [ "$sourc" == "copysource.txt" ]; then

    echo "The file name you entered was found!";

else
    echo "The file name you entered was invalid - please try again";
    echo -n "Enter the source file name: "
    read sourc
fi

echo -n "Enter the destination file name: "
read dest


if [ "$dest" == "copydest.txt" ]; then

    echo "The destination file name you entered was found!";

else
    echo "The destination file name you entered was invalid - please try         again";
    echo -n "Enter the destination file name: "
    read dest
fi


cp $sourc $dest
echo "copies $sourc to $dest"
echo "contents of $dest are: "
cat $dest

Answer 1

下面的代码检查两个文件（作为 $1 和 $2 传入）是否存在并将 $1 连接到 $2 （我认为这就是您想要做的）。如果其中一个文件尚不存在，系统将提示用户依次输入源文件名和目标文件名，直到输入现有文件 - ctrl-c 退出，否则！

#!/bin/bash
#Date: July 14 2016

# Use -f to test if files exist
if [[ -f "$1" ]] && [[ -f "$2" ]]; then
    echo "Appending contents of $1 to $2"
    # Use cat to take the contents of one file and append it to another
    cat "$1" >> "$2"
    echo "Contents of $2 are: "
    cat "$2"
    # Don't want to go any further so exit.
    exit
fi


# You could consider merging the logic above with that below
# so that you don't re-test both files if one of them exists, but the
# following will work.

clear
sourc=''
dest=''

while [[ ! -f "$sourc" ]]
do  
    echo -n "Enter the source file name: "
    read sourc

    if [ -f "$sourc" ]; then
        echo "The file name you entered was found!";
    else
        echo "The file name you entered was invalid - please try again";
    fi
done

while [[ ! -f "$dest" ]]
do
    echo -n "Enter the destination file name: "
    read dest

    if [ -f "$dest" ]; then
        echo "The file name you entered was found!";
    else
        echo "The file name you entered was invalid - please try again";
    fi
done

cat "$sourc" >> "$dest"
echo "Appending $sourc to $dest"
echo "Contents of $dest are: "
cat "$dest"

Answer 2

这是一个 shell 函数，应该可以解决问题

appendFile(){
  local iFile oFile;
  [ ! -f "$1" ] || [ -z "$2" ] && {
    while [ ! -f "$iFile" ]; do read -p "Input file: " -i "$1" iFile; done;
    read -i "$2" -p "Output file: " oFile;
  };
  cat "${iFile-$1}" >> "${oFile-$2}";
  cat "${oFile-$2}";
}