转义字符，

Question

在我的bash脚本，我试图执行以下Linux命令：

sed -i "/$data_line/ d" $data_dir 

$ data_line由用户输入的，它可能conatain特殊字符可能刹车正则表达式。 我在执行sed命令之前如何转义$ data_line中所有可能的特殊字符？

Answer 1

您可能能够使用这种技术来保护选择。下面标有“*****”的行是重要的行。其他人主要是为了测试和演示。关键是要使用不出现在用户输入中的字符来分隔选择器地址。

data_line='.*/ s/GOLD/LEAD/g;b;/.*' # scary user input 
candidates='/:.|@#%^&;,!~abcABC'  # ***** # (make it as long as you like) 
char=$(echo "$candidates" | tr -d "$data_line") # ***** 
char=${char:0:1} # ***** choose the first candidate that doesn't appear in the user input 

if [ -z "$char" ] # ***** this test checks for exhaustion of the candidate character set 
then 
    echo "Unusable user input. Recommendation: cigarette and blindfold." 
    exit 1 
fi 

# test without protection 
excitement="GOLD, I tell you, thar's GOLD in them thar hills!" 
echo "$excitement" | sed "/$data_line/ d" 
# output: "LEAD, I tell you, thar's LEAD in them thar hills!" 

# test WITH protection 
echo "$excitement" | sed "\\${char}${data_line}${char} d" # ***** 
# output: "GOLD, I tell you, thar's GOLD in them thar hills!" 

# test WITH protection and useful user input 
data_line="secret" 
mystery="The secret map is tucked in a hidden compartment in my saddle bag." 
echo -e "$excitement\n$mystery" | sed "\\${char}${data_line}${char} d" 
# output: "GOLD, I tell you, thar's GOLD in them thar hills!" 

Answer 2

grep -v -F "$data_line" "$data_dir" > ...