Replace string in a file with url present in another file in shell script-CodePudding

I was like trying to replace a string in a file with the url present in another file using sed command. for example... let url.txt be the file that contains url:

https://stackoverflow.com/questions/1483721/shell-script-printing-contents-of-variable-containing-output-of-a-command-remove

and demo.txt contains Replace_Url the sed command I used is:

sed -i "s/Replace_Url/$(sed 's:/:\\/:g' url.txt)/" demo.txt

there comes no error but the string hasn't been replaced..

CodePudding user response：

sed -i "s@Replace_Url@$(<url.txt)@" demo.txt it works

CodePudding user response：

It'd be hard to do this job robustly with sed since sed doesn't support literal string operations (see Is it possible to escape regex metacharacters reliably with sed), so just use awk instead, e.g.:

awk -v old='Replace_Url' '
    NR==FNR { new=$0; next }
    s=index($0,old) { $0 = substr($0,1,s-1) new substr($0,s length(old)) }
    { print }
' url.txt demo.txt