error on pipe in bash script

Question

part of my bash script is

A="-a"
B="|more"
ls $A $B

when executing this script, it complained "|more" not found. How to use pipelines in bash script commands then please?

Andriy M · Accepted Answer · 2011-08-03 05:31:30Z

2

Maybe like this:

eval "ls $A $B"

?

answered Aug 3, 2011 at 5:31

Andriy M

78k18 gold badges100 silver badges157 bronze badges

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

2 Comments

amphetamachine Over a year ago

eval is dangerous! What if A='`rm -rf' and B='/`'?

Andriy M Over a year ago

@amphetamachine: Yes, it is dangerous, as is the idea to make a single command out of bits the way the OP wants it.

amphetamachine · Accepted Answer · 2011-08-03 05:57:18Z

2

I think what you may be trying for is implementing some sort of variable that controls whether the data is piped through a pager.

You may be better off using alias:

if [ "$USING_PAGER" -ne 0 ]; then
    alias B='more'
else
    alias B='cat'
fi

ls $A |B

answered Aug 3, 2011 at 5:57

amphetamachine

30.9k12 gold badges68 silver badges74 bronze badges

1 Comment

Andriy M Over a year ago

Very nice. If the script is for general (public) use (which is probably oftener the case than not), this approach is much safer.

Petar Ivanov · Accepted Answer · 2011-08-03 05:32:06Z

0

ls -a |more

also fails - there is no such command in bash.

answered Aug 3, 2011 at 5:32

Petar Ivanov

93.4k11 gold badges84 silver badges95 bronze badges

3 Comments

Jacob Over a year ago

actually, most modern bashs are lax enough to allow "|more" without the space.

Andriy M Over a year ago

@cularis: Petar is possibly talking specifically about more, not |more. (Probably because it should be less.)

Petar Ivanov Over a year ago

yeah exactly, sorry, I got distracted :)

Collectives™ on Stack Overflow

error on pipe in bash script

3 Answers 3

2 Comments

1 Comment

3 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

2 Comments

1 Comment

3 Comments

Your Answer

Sign up or log in

Post as a guest

Related