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# 1  
Old 05-10-2011
Readline programming
Hi,

I am new to using readline library to my application. Please I want to no how to write code for command line switches(options), i.e when i press tab the option of command as to change.
eg:
Code:
ls -a
ls -d

...so on ls as many options, here i want options to be completed using tab

Please any one could help on this really appreciated.
Thank you

Moderator's Comments:
Mod Comment Please use [code] and [/code] tags when posting code, data or logs etc. to preserve formatting and enhance readability, thanks.
Last edited by zaxxon; 05-10-2011 at 07:07 AM.. Reason: code tags
# 2  
Old 05-10-2011
Do you want to setup auto-completion of options?
# 3  
Old 05-10-2011
I think you've got something mixed up here.

readline is used if you want your application to present interactive input including line editing and history.

getopt from the GNU libc is used to parse command line options.

Command line completion as you describe it is provided by the shell, not the application. It's provided by the bash completion package for bash, and zsh is already shipped with that feature. These extensions are configured using shell commands and scripts.
This User Gave Thanks to pludi For This Post:
vanid
# 4  
Old 05-11-2011
Readline Probelm
Hi,

actually for command line auto completion i knew that using shell.....but we see interactive command line args completion can done by tab key using gnu readline library...up to this i knew but here i want command line switches completion using tab

---------- Post updated at 11:45 PM ---------- Previous update was at 11:29 PM ----------

here wht I want is:
Just type your command, a dash (-) and type tab. The shell will show you available switches.
For example, try:
root@ubuntu:~# ls -
and press tab - Surprise!
-a -c -b -d
-A -author -B -f .... so on options that available with ls command.
# 5  
Old 05-11-2011
mhmm, if you are using Bash you could achieve this by using only Bash's built-in `complete' and a couple of other commands. Or as suggested by pludi you could have a look at the bash autocompletion package or I could post my own function which does the same job and which I have written a few years ago. Below is just an example of how it works:
Code:
sidorenko@sidorenko>
0 ~>autocomplete_options ls

sidorenko@sidorenko>
0 ~>ls -  pressing tab
-1                                         -l
-a                                         -L
-A                                         -m
--author                                   -n
-b                                         -N
-B                                         -o
--block-size=                              -p
-c                                         -q
-C                                         -Q
--color                                    --quoting-style=
--color=                                   -r
-d                                         -R
-D                                         -s
--dereference-command-line-symlink-to-dir  -S
-f                                         --show-control-chars
-F                                         --si
--file-type                                --sort=
--format=                                  -t
--full-time                                -T
-g

Though when I was reading the help for the `complete' built-in, I came across the following line:
Quote:
>help complete
complete: complete [-abcdefgjksuv] [-pr] [-DE] [-o option] [-A action] [-G globpat] [-W wordlist] [-F function] [-C command] [-X filterpat] [-P prefix] [-S suffix] [name ...]
Specify how arguments are to be completed by Readline.
I don't know what is meant here with Readline - maybe some C library or whatever. Do you mean this Readline?

---------- Post updated at 02:02 AM ---------- Previous update was at 01:53 AM ----------

On Linux I've indeed found such a function:
Code:
SYNOPSIS
       #include <stdio.h>
       #include <readline/readline.h>
       #include <readline/history.h>

       char *
       readline (const char *prompt);

This User Gave Thanks to sidorenko For This Post:
vanid
# 6  
Old 05-12-2011
Readline Programming
Hi,

Thank you so much for a usefull solution. Exactly this is what iam looking for but this is here for bash right? so now i want it using readline. Yes the same readline what i mean...which linux gnu readline library. Please can u post the function you have with you.which does same above action..which may help out from this issue.

Thanks again

---------- Post updated at 05:00 AM ---------- Previous update was at 04:52 AM ----------

And also you said you ahve your own fuction which is written few years back...........please could you provide me that fuction so that it may help me.
Last edited by vanid; 05-12-2011 at 07:19 AM..
# 7  
Old 05-12-2011
Again, the completion suggestions are done by the shell, not the application. Your application isn't even loaded at that point, and thus has no way of telling the shell what options are available. The readline library would only be of interest if you want that functionality inside your application (like GDB when used interactive), and even then you'd have to extend the functionality yourself.
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