I'm not exactly sure what I'm doing wrong with this one. I'm trying to run the command

alias localip='ip -4 -o addr show eth0 | egrep -o '([[:digit:]]{1,3}\.){3}[[:digit:]]{1,3}' | head -n 1'

If I run the command

ip -4 -o addr show eth0 | egrep -o '([[:digit:]]{1,3}\.){3}[[:digit:]]{1,3}' | head -n 1

I get the result I expect, however, when trying to create an alias with the command, I get

-bash: syntax error near unexpected token `('

Any help would be appreciated. TIA.


You're nesting single quotes within single quotes. That doesn't work.

Try using "double quotes" in the inner expression.

| improve this answer | |

I found it a much cleaner solution to just create a function and name your alias after the function, like this:

alias localip=GetLocalIP

function GetLocalIP()
   ip -4 -o addr show eth0 | egrep -o '([[:digit:]]{1,3}\.){3}[[:digit:]]{1,3}' | head -n 1
| improve this answer | |
  • 5
    What's the advantage of creating an alias to a function, rather than just naming the function localip? Also, the function keyword breaks compatibility with other shells. I'd suggest just using localip() { ... – Tom Fenech Jan 9 '16 at 15:33
  • @TomFenech Your suggestion works in general. It's just a personal style that works for me: All my functions start with a verb, so that it makes sense in code (reused elsewhere). . However, that style slows me down when it comes to CLI typing. So alias comes as a compromise. Verbosity like the function keyword helps me define code parsers or generators later. – kakyo Apr 17 '19 at 2:25

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