jim mcnamara -
thank you, very much, everything clear and usefull for me now!
I am realy exiting to understand it. Now I have new (for me ) possibility in scripting and in shell.
Definetely, 'eval' gives usefull opportunity!
The 'exec' - nice to know that and it is good to use it, too.
The 'sorce' - it appeared that I have used it already for long time (as '. script') but did not realized tha all definishions of the curent shell are available in runing script by that (other part - backward - usualy is a reason to use the '. scr')
I've just tryed it and maybe it would be usefull to show it here, too, although your explanation pretty enough, but, anyway, here it is:
I am using ksh88 and I am trying to catch the return status of opening a file using a file descriptor and the exec and eval commands. However I am not having much success. Here is what I have:
eval "exec $next_fh>$1"
This opens the file if the file is $1 is valid, however I want to make... (1 Reply)
Hi everybody !
I writed php code so exec bash shell via php (SMS Send via bash shell) but i have problem as follow :
1. When i exec from linux mode : ./sms.sh --- output is "Messages ... OK". Then all message has been sent.
2. When i exec from PHP site --- return value is "Message ... OK" on... (1 Reply)
how does exec() do it? on successful call of exec() family of functions, they never return...
how to i emulate that.
assume the standard example,
execl("/bin/ls","ls",NULL);
now this would never return.
i m trying to emulate exec()'s never to return feature...
#include<unistd.h>... (4 Replies)
I do not claim to be an expert, but I have done things with scripts that whole teams of folks have said can not be done. Of course they should have said we do not have the intestinal fortitude to git-r-done.
I have been using UNIX actually HPUX since 1992. Unfortunately my old computer died and... (7 Replies)
Okay so I am just starting programming c++. I just started started to red "C++ for Dummies yesterday and theres a lot of things I do not understand from this book and this source code especially. I will first post the full source code and then post questions about certain thing, usually what they... (2 Replies)
Hi
i am in learning phase of unix.
i was going through exec in a unix book. below is the command
exec n>file
exec n>>file
however when i used the exec command like below , where ex is the file name
exec 2>>exand then do ls -lrt then again when i do the ls -lrt to see the size of the file... (3 Replies)
Working on some source I've found some strange declaration in included header file.
I am looking for someone's help to understand me that syntax's, as it is fine (it is compiled without any complain,) but for me it seems out of any sense!
Acctually, it warning by CC compiler: " Warning: Implicit... (1 Reply)
Just began to learn on Shell Script. I got an exercise from my friend. I know how to make this happen in C, but I'm not familiar with Shell Script. Hope I can get some help from all of you.
I want to write a bash script to comment code blocks in a bash source file. What I mean comment is '#', I... (1 Reply)
I am still learning shell scripting. Recently I see a function for read configuration. But some of special character make me confused. I checked online to find answer. It was not successful. I post the code here to consult with expert or guru to get better understanding on these special characters... (3 Replies)
Discussion started by: duke0001
3 Replies
LEARN ABOUT SUSE
which
WHICH(1) General Commands Manual WHICH(1)NAME
which - shows the full path of (shell) commands.
SYNOPSIS
which [options] [--] programname [...]
DESCRIPTION
Which takes one or more arguments. For each of its arguments it prints to stdout the full path of the executables that would have been exe-
cuted when this argument had been entered at the shell prompt. It does this by searching for an executable or script in the directories
listed in the environment variable PATH using the same algorithm as bash(1).
This man page is generated from the file which.texinfo.
OPTIONS --all, -a
Print all matching executables in PATH, not just the first.
--read-alias, -i
Read aliases from stdin, reporting matching ones on stdout. This is useful in combination with using an alias for which itself. For
example
alias which='alias | which -i'.
--skip-alias
Ignore option `--read-alias', if any. This is useful to explicity search for normal binaries, while using the `--read-alias' option in
an alias or function for which.
--read-functions
Read shell function definitions from stdin, reporting matching ones on stdout. This is useful in combination with using a shell func-
tion for which itself. For example:
which() { declare -f | which --read-functions $@ }
export -f which
--skip-functions
Ignore option `--read-functions', if any. This is useful to explicity search for normal binaries, while using the `--read-functions'
option in an alias or function for which.
--skip-dot
Skip directories in PATH that start with a dot.
--skip-tilde
Skip directories in PATH that start with a tilde and executables which reside in the HOME directory.
--show-dot
If a directory in PATH starts with a dot and a matching executable was found for that path, then print "./programname" rather than the
full path.
--show-tilde
Output a tilde when a directory matches the HOME directory. This option is ignored when which is invoked as root.
--tty-only
Stop processing options on the right if not on tty.
--version,-v,-V
Print version information on standard output then exit successfully.
--help
Print usage information on standard output then exit successfully.
RETURN VALUE
Which returns the number of failed arguments, or -1 when no `programname' was given.
EXAMPLE
The recommended way to use this utility is by adding an alias (C shell) or shell function (Bourne shell) for which like the following:
[ba]sh:
which ()
{
(alias; declare -f) | /usr/bin/which --tty-only --read-alias --read-functions --show-tilde --show-dot $@
}
export -f which
[t]csh:
alias which 'alias | /usr/bin/which --tty-only --read-alias --show-dot --show-tilde'
This will print the readable ~/ and ./ when starting which from your prompt, while still printing the full path when used from a script:
> which q2
~/bin/q2
> echo `which q2`
/home/carlo/bin/q2
BUGS
The HOME directory is determined by looking for the HOME environment variable, which aborts when this variable doesn't exist. Which will
consider two equivalent directories to be different when one of them contains a path with a symbolic link.
AUTHOR
Carlo Wood <carlo@gnu.org>
SEE ALSO bash(1)WHICH(1)