variable inside awk/sed in alias

Question

I'd like to write an alias that would print particular line from all files in a folder, i.e.:
$ print_line 20 - would print 20th line from all files in a folder.

I spent hour with various constructions in .bashrc (some examples below), with lot of different escaping, but so far nothing worked. Thanks for any help.

alias a="for f in create*; do sed -n '\$1{p;q}' $f; done"

alias b="for f in create*; do awk 'NR==\$1{print $0}' $f; done"

function l { r=$(echo \'"$1"{p;q}\'); sed -n "$r" *; }

Answer 1

You can try this,

printline() { for f in create*; do sed -n "$1{p;q}" $f; done ;}

Answer 2

bash aliases, unlike those in csh, do not allow parameters; see Make a Bash alias that takes a parameter? and Passing argument to alias in bash, and How to pass command line arguments to a shell alias? and How do I include parameters in a bash alias?

So you need a function. If you have the GNU sed with the -s switch, the following will work:

   printline() { sed -ns "$1 p" create*;} 

Otherwise, slightly modifying sat's nice answer, use a for-loop:

   printline() { for f in create*; do sed -n "$1 p" "$f"; done;}

Note the space after the { is necessary. The use of double-quotes in "$f" guards against filenames with bad characters, such as spaces or stars.