它不优雅,它不起作用,但现在它看起来像这样：

#!/bin/bash

# Often users have a messed up cache folder -- one that was redirected
# but now is just a broken symlink.  This script checks to see if
# the cache folder is all right,and if not,deletes it
# so that the system can recreate it.

USERNAME=$3
if [ "$USERNAME" == "" ] ; then
    echo "This script must be run at login!" >&2
    exit 1
fi

DIR="~$USERNAME/Library/Caches"

cd $DIR || rm $DIR && echo "Removed misdirected Cache folder" && exit 0

echo "Cache folder was fine."

问题的关键在于波浪扩展不能像我想的那样工作.

让我们说我有一个名为george的用户,他的主文件夹是/ a / path / to / georges_home.如果,在shell,我输入：

cd ~george

它需要我到适当的目录.如果我输入：

HOME_DIR=~george
echo $HOME_DIR

它给了我：

/a/path/to/georges_home

但是,如果我尝试使用变量,它不起作用：

USERNAME="george"
cd ~$USERNAME
-bash: cd: ~george: No such file or directory

我尝试过使用引号和反引号,但无法弄清楚如何使其正确扩展.我该如何工作？

附录

我只是想发布我已完成的脚本(实际上,它并不像上面正在进行的工作一样丑陋！)并说它似乎正常工作.

#!/bin/bash

# Often users have a messed up cache folder -- one that was redirected
# but now is just a broken symlink.  This script checks to see if
# the cache folder is all right,deletes it
# so that the system can recreate it.

#set -x # turn on to help debug

USERNAME=$3 # Casper passes the user name as parameter 3
if [ "$USERNAME" == "" ] ; then
    echo "This script must be run at login!" >&2
    exit 1  # bail out,indicating failure
fi

CACHEDIR=`echo $(eval echo ~$USERNAME/Library/Caches)`

# Show what we've got
ls -ldF "$CACHEDIR"

if [ -d "$CACHEDIR" ] ; then
    # The cache folder either exists or is a working symlink
    # It doesn't really matter,but might as well output a message stating which
    if [ -L "$CACHEDIR" ] ; then
        echo "Working symlink found at $CACHEDIR was not removed."
    else
        echo "Normal directory found at $CACHEDIR was left untouched."
    fi
else
    # We almost certainly have a broken symlink instead of the directory
    if [ -L "$CACHEDIR" ] ; then
        echo "Removing broken symlink at $CACHEDIR."
        rm "$CACHEDIR"
    else
        echo "Abnormality found at $CACHEDIR.  Trying to remove." >&2
        rm -rf "$CACHEDIR"
        exit 2  # mark this as a bad attempt to fix things; it isn't clear if the fix worked
    fi
fi

# exit,indicating that the script ran successfully,# and that the Cache folder is (almost certainly) now in a good state
exit 0