LinuxQuestions.org - shell scripting/ the fc -l command !

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shell scripting/ the fc -l command !

i wrote the following program:

# !/bin/bash
#profile program
function histoire {
HISTSIZE=20
echo “HISTSIZE est égale à” $HISTSIZE
echo “le numéro de la commande est” $fc $-l
}
histoire
exit 0

can someone tell me, why am i not getting the same result, as in when i directly write the command fc -l ? and whats hBl ?

knoppix@knoppix:/ramdisk/home/knoppix/tmp$ chmod +x .profile
+ chmod +x .profile
knoppix@knoppix:/ramdisk/home/knoppix/tmp$ ./.profile
+ ./.profile
HISTSIZE est égale à 20
le numéro de la commande est hBl

where did you read that "$fc $-l" would do what you want? that means nothing.... try "$((fc -l))" instead.

well after trying $(fc -l )
the only thing that wouldnt give me errors was $fc$-l !!

i tried $((fc -l)), but that gives me 0, i want the same list that i get when i simply type fc -l on the xterm !

how can i do that? any idea ?

yeah it does doesn't it? retard alert.... i knew it didn't look right... sorry, it does basic expression evalution...

# echo $(( 10 + 10 ))

20

you do need $(fc -l) or `fc -l` to actually execute fc as a command. i don't think that that's really useful to you though as it'll print it all on one line... i'd just put the fc command on a new line by itself.

doh! :)

neither 'fc -l' nor $(fc -l) worked !
i already tried those two,
maybe i should add some argument or sthg? i cant get the answer that i want,

$(fc -l) gives me hBl as an answer !!
and 'fc -l' gives me fc -l as an answer !!

actually $fc $-l gives me hBl as an answer
$(fc -l) gives me nth as an answer !!

no it's `fc -l` not 'fc -l' but as above i don't think you should use that mechanism at all, just run it normally outside of echo.

what do you mean by outside of echo ?

i have this program:i changed the fc -l command :

# !/bin/bash
#profile program
function histoire {
HISTSIZE=20
echo “HISTSIZE est égale à” $HISTSIZE
echo “le numéro de la commande est” `fc -l`
}
histoire
exit 0

BUT I GET NOTHG AS AN ANSWER !

# !/bin/bash
#profile program
function histoire {
HISTSIZE=20
echo “HISTSIZE est égale à” $HISTSIZE
echo “le numéro de la commande est”
fc -l
}
histoire
exit 0

this also gives me "nthg" as an answer !

do you atually mean "nothing"...? or literally a text string as you wrote?? if fc -l doesn't give you an output, then you have no recorded history to output...

yes i actually mean nthg, just blank space ,
i have a recorded history to output, and i know that because when i type fc -l in my xterm then i get a long list !!

Quote:

Originally Posted by mayaabboud (Post 3009666)

can someone tell me, why am i not getting the same result, as in when i directly write the command fc -l ? and whats hBl ?

Both of these questions have simple explanations. First, let’s see what fc does (taken from here):

Quote:

Originally Posted by The Open Group Base Specifications Issue 6

The fc utility shall list, or shall edit and re-execute, commands previously entered to an interactive sh.

As you can see, fc only works (or should only work) on an interactive shell (i.e., one in which you can interactively type commands).

For example, consider this simple program (which I will save in a text file named program):

Code:

#!/bin/sh



fc -l

Now, watch what happens when I try to execute it as a script:

Code:

$ chmod +x program

$ ./program

$

And watch what happens if I source it into my interactive shell:

Code:

$ source program

1        cd /tmp

2        cat > program

3        chmod +x program 

4        ./program

$

As for “hBl”, this is the result expanding “$-l” in a script. You see, it shall be parsed as “${-}l” where the internal variable $- has the flags currently set (this is a ksh-ism borrowed by bash). In this case, the flags set are for brace expansion and command hashing.