Define function in unix/linux command line (e.g. BASH)

Question

Sometimes I have a one-liner that I am repeating many times for a particular task, but will likely never use again in the exact same form. It includes a file name that I am pasting in from a directory listing. Somewhere in between and creating a bash script I thought maybe I could just create a one-liner function at the command line like:

numresults(){ ls "$1"/RealignerTargetCreator | wc -l } 

I've tried a few things like using eval, using numresults=function..., but haven't stumbled on the right syntax, and haven't found anything on the web so far. (Everything coming up is just tutorials on bash functions).

Answer 1

Quoting my answer for a similar question on Ask Ubuntu:

Functions in bash are essentially named compound commands (or code blocks). From man bash:

Compound Commands    A compound command is one of the following:    ...    { list; }           list  is simply executed in the current shell environment.  list           must be terminated with a newline or semicolon.  This  is  known           as  a  group  command.   ... Shell Function Definitions    A shell function is an object that is called like a simple command  and    executes  a  compound  command with a new set of positional parameters.    ... [C]ommand is usually a list of commands between { and },  but    may  be  any command listed under Compound Commands above. 

There's no reason given, it's just the syntax.

Try with a semicolon after wc -l:

numresults(){ ls "$1"/RealignerTargetCreator | wc -l; } 

Answer 2

Don't use ls | wc -l as it may give you wrong results if file names have newlines in it. You can use this function instead:

numresults() { find "$1" -mindepth 1 -printf '.' | wc -c; }