Alias bash one line script

Question

I have to do an alias called for example "longest" for this script:

data=""; len=0; line=""; while [[ $line != "quit" ]]; do read line; [[ $line != "quit" ]] && [[ ${#line} -gt len ]] && len=${#line} data=$line; done; echo $len; echo $data 1>2

Its job is simply reading words or phrases and counting the characters.

I put the script inside quotes like this:

alias longest="...script..."

but it doesn't work and I don't know why. Can anyone explain to me why? A possible solution?

Why dont you simply write a script, make it executable and call it? — Michail Alexakis
– Michail Alexakis, Commented May 15, 2022 at 18:45
This absolutely should not be an alias. But, as a first attempt, try just using single quotes: alias longest=' ... ' — William Pursell
– William Pursell, Commented May 15, 2022 at 19:02
Did you really mean to send output to a file named "2"? If you're trying to send output to stderr, use 1>&2 (or just >&2) rather than 1>2. Also, there are a bunch of things in there that really should be double-quoted to avoid parsing weirdness. Finally, I'd recommend stopping on end-of-file as well as/instead of when getting "quit" (you could use while read line && [[ $line != "quit" ]]; do ... to check for either). — Gordon Davisson
– Gordon Davisson, Commented May 15, 2022 at 20:46

knittl · Accepted Answer · 2022-05-16 18:17:00Z

2

You have several options (and I'm repeating the script from the question, not fixing any other errors (?) like redirecting to a file with name 2):

Have the alias define a function and execute it immediately

alias longest='f() { data=""; len=0; line=""; while [[ $line != "quit" ]]; do read line; [[ $line != "quit" ]] && [[ ${#line} -gt len ]] && len=${#line} data=$line; done; echo $len; echo $data 1>2; }; f'

Create a script and save it in a directory from your PATH, usually ~/bin:

File ~/bin/longest:

#!/bin/bash
data="";
len=0;
line="";
while [[ $line != "quit" ]]; do
   read line;
   [[ $line != "quit" ]] && [[ ${#line} -gt len ]] && len=${#line} data=$line;
done;
echo $len;
echo $data 1>2

and finally chmod +x ~/bin/longest.

Define the function in your .bashrc file and then call it on demand.
Avoid the complicated, home-grown code and go for something much simpler. The behavior and output will not be identical, but should be sufficient.
```
alias longest="awk '{print length, \$0}' | sort -nr | head -1"
```

edited May 16, 2022 at 18:17

answered May 15, 2022 at 19:18

knittl

269k59 gold badges339 silver badges405 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

Gordon Davisson Over a year ago

Why wrap a function in an alias instead of just defining & using the function it directly? Wrapping it in an alias just seems like useless complexity (& opportunity for parsing confusion). Speaking of which, in the awk version, you need to escape the $ to keep $0 from being expanded (since it's in double-quotes as the alias is being defined).

knittl Over a year ago

@GordonDavisson thanks for the hint, I have fixed the awk example. As for why a function in an alias? Because the question was asking for a way to do this with an alias. I provided other options to suggest different solutions that do not necessarily involve a (complicated) alias.

Collectives™ on Stack Overflow

Alias bash one line script

1 Answer 1

2 Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

2 Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related