168

I am trying to create an aliases in bash. What I want to do is map ls -la to ls -la | more

In my .bashrc file this is what I attempted:

alias 'ls -la'='ls -la | more'

However it does not work because (I assume) it has spaces in the alias name. Is there a work around for this?

Jesse Nickles
  • 111
sixtyfootersdude
  • 8,449

4 Answers4

196

The Bash documentation states "For almost every purpose, shell functions are preferred over aliases." Here is a shell function that replaces ls and causes output to be piped to more if the argument consists of (only) -la.

ls() {
    if [[ $@ == "-la" ]]; then
        command ls -la | more
    else
        command ls "$@"
    fi
}

As a one-liner:

ls() { if [[ $@ == "-la" ]]; then command ls -la | more; else command ls "$@"; fi; }

Automatically pipe output:

ls -la
Dennis Williamson
  • 111,445
77

From the alias man page:

The first word of each simple command, if unquoted, is checked to see if it has an alias. If so, that word is replaced by the text of the alias. The alias name and the replacement text may contain any valid shell input, including shell metacharacters, with the exception that the alias name may not contain `='.

So, only the first word is checked for alias matches which makes multi-word aliases impossible. You may be able to write a shell script which checks the arguments and calls your command if they match and otherwise just calls the normal ls (See @Dennis Williamson's answer)

Community
  • 1
heavyd
  • 65,321
24

A slightly improved approach taken from Dennis' answer:

function ls() {
  case $* in
    -la* ) shift 1; command ls -la "$@" | more ;;
    * ) command ls "$@" ;;
  esac
}

Or the one-liner:

function ls() { case $* in -la* ) shift 1; command ls -la "$@" | more ;; * ) command ls "$@" ;; esac }

This allows for further options/arguments to be appended after the command if needed, for example ls -la -h

ld_pvl
  • 359
  • 3
  • 8
-1

You can invoke this alias still, but you need quotation in order that the space is part of the command word. So "ls -la" -p pattern will pass the -p pattern option to more, not ls.

Charles Stewart
  • 2,952