Re: [Haskell-cafe] How to get a file path to the program invoked?
Hi I was running into a similar problem while working on GHC not long ago - short version is that it's not even possible to find out the executable path portably from C [1]. Using argv[0] just gave me the path of the GHC wrapper script, for example - as it uses exec without -a. The whole thing is easiest if you're on Linux: getExePath = readSymbolicLink /proc/self/exe On all other operation system, one needs to start mucking around with custom kernel calls. Or, more realistically, try to find a way around requiring it... Greetings, Peter Wortmann [1] http://stackoverflow.com/questions/1023306 ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] How to get a file path to the program invoked?
May I ask what the problem is you're trying to solve?
If you want to access datafiles in an installed program then Cabal can
help you with that. See
http://www.haskell.org/cabal/users-guide/#accessing-data-files-from-package-code
If you want to do more complicated things, maybe take a look at how
GHC does it. For example, on OS X (and other Unix-based systems) the
ghc command is actually a script:
$ cat `which ghc`
#!/bin/sh
exedir=/Library/Frameworks/GHC.framework/Versions/7.0.3-x86_64/usr/lib/ghc-7.0.3
exeprog=ghc-stage2
executablename=$exedir/$exeprog
datadir=/Library/Frameworks/GHC.framework/Versions/7.0.3-x86_64/usr/share
bindir=/Library/Frameworks/GHC.framework/Versions/7.0.3-x86_64/usr/bin
topdir=/Library/Frameworks/GHC.framework/Versions/7.0.3-x86_64/usr/lib/ghc-7.0.3
pgmgcc=/Developer/usr/bin/gcc
executablename=$exedir/ghc
exec $executablename -B$topdir -pgmc $pgmgcc -pgma $pgmgcc
-pgml $pgmgcc -pgmP $pgmgcc -E -undef -traditional ${1+$@}
/ Thomas
On 1 December 2011 16:12, dokondr doko...@gmail.com wrote:
Hi,
When my program starts it needs to know a complete path to the directory
from which it was invoked.
In terms of standard shell (sh) I need the Haskell function that will do
equivalent to:
#!/bin/sh
path=$(dirname $0)
How to get this path in Haskell?
getProgName :: IO String
defined System.Environment only returns a file name of the program without
its full path.
Thanks!
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Re: [Haskell-cafe] How to get a file path to the program invoked?
On Thu, Dec 15, 2011 at 09:48, Peter Wortmann sc...@leeds.ac.uk wrote: path portably from C [1]. Using argv[0] just gave me the path of the GHC wrapper script, for example - as it uses exec without -a. Note that exec -a is a bash-ism and not portable to POSIX shells (ash on *BSD, dash on Debian/Ubuntu, etc.) or traditional /bin/sh as still shipped with some commercial Unixes. -- brandon s allbery allber...@gmail.com wandering unix systems administrator (available) (412) 475-9364 vm/sms ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] How to get a file path to the program invoked?
On 16/12/2011, at 11:55 AM, Brandon Allbery wrote: Note that exec -a is a bash-ism and not portable to POSIX shells Recent versions of ksh also support this, so it's not just bash. But there are certainly a lot of POSIX shells that don't, including the version of ksh on my main machine. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] How to get a file path to the program invoked?
In addition to argv[0] http://hackage.haskell.org/packages/archive/system-argv0/0.1/doc/html/System-Argv0.html There is also this package: http://hackage.haskell.org/packages/archive/FindBin/0.0.5/doc/html/System-Environment-FindBin.html System-Argv0 has special cases for windows- FindBin may not work there. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] How to get a file path to the program invoked?
This is how I finally solved this problem for POSIX complaint system:
--
-- TestRun
--
module Main where
import System.Cmd (rawSystem)
import System.Directory (getCurrentDirectory)
import System.Environment.Executable (ScriptPath(..), getScriptPath)
import System.FilePath.Posix (splitFileName)
main = do
path - getMyPath
putStrLn $ myPath = ++ path
let cmdLine = path ++ args.sh
rawSystem cmdLine [iphone, test-twitts.txt]
{--
data ScriptPath Source
Constructors:
Executable FilePathit was (probably) a proper compiled executable
RunGHC FilePathit was a script run by runghc/runhaskell
Interactive we are in GHCi
--}
getMyPath = do
curDir - getCurrentDirectory -- from System.Directory
scriptPath - getScriptPath -- from System.Environment.Executable
let path = getMyPath' scriptPath curDir
return path
getMyPath' (Executable path) _ = fst (splitFileName path)
getMyPath' (RunGHC path) _ = fst (splitFileName path)
getMyPath' Interactive curDir = curDir++/
--
All the best,
Dmitri O. Kondratiev
This is what keeps me going: discovery
doko...@gmail.com
http://sites.google.com/site/dokondr/welcome
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Re: [Haskell-cafe] How to get a file path to the program invoked?
Balazs, thanks for your comments!
The first comment works just fine.
With / operator I get this:
Main System.Environment.Executable System.FilePath /abc / /
/
Instead of getting /abc/ I get /. What am I doing wrong?
On Mon, Dec 5, 2011 at 6:03 PM, Balazs Komuves bkomu...@gmail.com wrote:
Two small comments:
1) This should work on Windows too, if you just leave out the word Posix
from the source:
import System.FilePath (splitFileName)
2) In general when dealing with paths, use the / operator (from
System.FilePath)
instead of ++ / ++
Balazs
On Mon, Dec 5, 2011 at 1:44 PM, dokondr doko...@gmail.com wrote:
This is how I finally solved this problem for POSIX complaint system:
--
-- TestRun
--
module Main where
import System.Cmd (rawSystem)
import System.Directory (getCurrentDirectory)
import System.Environment.Executable (ScriptPath(..), getScriptPath)
import System.FilePath.Posix (splitFileName)
main = do
path - getMyPath
putStrLn $ myPath = ++ path
let cmdLine = path ++ args.sh
rawSystem cmdLine [iphone, test-twitts.txt]
{--
data ScriptPath Source
Constructors:
Executable FilePathit was (probably) a proper compiled executable
RunGHC FilePathit was a script run by runghc/runhaskell
Interactive we are in GHCi
--}
getMyPath = do
curDir - getCurrentDirectory -- from System.Directory
scriptPath - getScriptPath -- from System.Environment.Executable
let path = getMyPath' scriptPath curDir
return path
getMyPath' (Executable path) _ = fst (splitFileName path)
getMyPath' (RunGHC path) _ = fst (splitFileName path)
getMyPath' Interactive curDir = curDir++/
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Re: [Haskell-cafe] How to get a file path to the program invoked?
Hi. On 5 December 2011 14:53, dokondr doko...@gmail.com wrote: Main System.Environment.Executable System.FilePath /abc / / / Instead of getting /abc/ I get /. What am I doing wrong? It thinks the second path is an absolute path. Combine two paths, if the second path isAbsolute, then it returns the second. http://hackage.haskell.org/packages/archive/filepath/latest/doc/html/System-FilePath-Posix.html#v:combine HTH, Ozgur ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] How to get a file path to the program invoked?
On Monday 05 December 2011, 15:53:35, dokondr wrote: Balazs, thanks for your comments! The first comment works just fine. With / operator I get this: Main System.Environment.Executable System.FilePath /abc / / / Instead of getting /abc/ I get /. What am I doing wrong? The second path is absolute. / is an alias for combine, the docs for that say: Combine two paths, if the second path isAbsolute, then it returns the second. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] How to get a file path to the program invoked?
The operator / is an alias for `combine`, which the documentation says:
Combine two paths, if the second path isAbsolute, then it returns the second.
In this case, / is absolute, so it is returned.
If you wish to add a trailing path separator, use `addTrailingPathSeparator`.
Erik
On Mon, Dec 5, 2011 at 15:53, dokondr doko...@gmail.com wrote:
Balazs, thanks for your comments!
The first comment works just fine.
With / operator I get this:
Main System.Environment.Executable System.FilePath /abc / /
/
Instead of getting /abc/ I get /. What am I doing wrong?
On Mon, Dec 5, 2011 at 6:03 PM, Balazs Komuves bkomu...@gmail.com wrote:
Two small comments:
1) This should work on Windows too, if you just leave out the word Posix
from the source:
import System.FilePath (splitFileName)
2) In general when dealing with paths, use the / operator (from
System.FilePath)
instead of ++ / ++
Balazs
On Mon, Dec 5, 2011 at 1:44 PM, dokondr doko...@gmail.com wrote:
This is how I finally solved this problem for POSIX complaint system:
--
-- TestRun
--
module Main where
import System.Cmd (rawSystem)
import System.Directory (getCurrentDirectory)
import System.Environment.Executable (ScriptPath(..), getScriptPath)
import System.FilePath.Posix (splitFileName)
main = do
path - getMyPath
putStrLn $ myPath = ++ path
let cmdLine = path ++ args.sh
rawSystem cmdLine [iphone, test-twitts.txt]
{--
data ScriptPath Source
Constructors:
Executable FilePath it was (probably) a proper compiled executable
RunGHC FilePath it was a script run by runghc/runhaskell
Interactive we are in GHCi
--}
getMyPath = do
curDir - getCurrentDirectory -- from System.Directory
scriptPath - getScriptPath -- from System.Environment.Executable
let path = getMyPath' scriptPath curDir
return path
getMyPath' (Executable path) _ = fst (splitFileName path)
getMyPath' (RunGHC path) _ = fst (splitFileName path)
getMyPath' Interactive curDir = curDir++/
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Re: [Haskell-cafe] How to get a file path to the program invoked?
Thanks,
'addTrailingPathSeparator' works just fine !
On Mon, Dec 5, 2011 at 7:52 PM, Erik Hesselink hessel...@gmail.com wrote:
The operator / is an alias for `combine`, which the documentation says:
Combine two paths, if the second path isAbsolute, then it returns the
second.
In this case, / is absolute, so it is returned.
If you wish to add a trailing path separator, use
`addTrailingPathSeparator`.
Erik
On Mon, Dec 5, 2011 at 15:53, dokondr doko...@gmail.com wrote:
Balazs, thanks for your comments!
The first comment works just fine.
With / operator I get this:
Main System.Environment.Executable System.FilePath /abc / /
/
Instead of getting /abc/ I get /. What am I doing wrong?
On Mon, Dec 5, 2011 at 6:03 PM, Balazs Komuves bkomu...@gmail.com
wrote:
Two small comments:
1) This should work on Windows too, if you just leave out the word
Posix
from the source:
import System.FilePath (splitFileName)
2) In general when dealing with paths, use the / operator (from
System.FilePath)
instead of ++ / ++
Balazs
On Mon, Dec 5, 2011 at 1:44 PM, dokondr doko...@gmail.com wrote:
This is how I finally solved this problem for POSIX complaint system:
--
-- TestRun
--
module Main where
import System.Cmd (rawSystem)
import System.Directory (getCurrentDirectory)
import System.Environment.Executable (ScriptPath(..), getScriptPath)
import System.FilePath.Posix (splitFileName)
main = do
path - getMyPath
putStrLn $ myPath = ++ path
let cmdLine = path ++ args.sh
rawSystem cmdLine [iphone, test-twitts.txt]
{--
data ScriptPath Source
Constructors:
Executable FilePathit was (probably) a proper compiled executable
RunGHC FilePathit was a script run by runghc/runhaskell
Interactive we are in GHCi
--}
getMyPath = do
curDir - getCurrentDirectory -- from System.Directory
scriptPath - getScriptPath -- from System.Environment.Executable
let path = getMyPath' scriptPath curDir
return path
getMyPath' (Executable path) _ = fst (splitFileName path)
getMyPath' (RunGHC path) _ = fst (splitFileName path)
getMyPath' Interactive curDir = curDir++/
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Re: [Haskell-cafe] How to get a file path to the program invoked?
Quoth wren ng thornton w...@freegeek.org, There was a discussion about this recently over on libraries@, IIRC. The short answer is that, at present, there is no function to give you $0. We'd like to add such a function, but it's not been done yet. Part of the problem is that, as Alexey says, the first element of argv is just whatever is passed to exec, which is not guaranteed to be a complete path, a canonical path, or any other specific thing we'd desire. It's not at all straightforward to determine the actual location of the executable, especially not in a platform-independent manner. argv[0] can't be trusted, scanning through $PATH isn't guaranteed to find it (and even if you find something of the right name, it's not guaranteed to be the correct executable), etc etc. This isn't your problem, though. I mean, if the proposed function is to return the path to the executable file, then indeed you have a big problem with argv[0]. argv[0] can be anything - or nothing (it can be a null string.) But if we've turned to the question of whether to return argv[0], that's much simpler: you don't need to consider why a programmer might want it. It's appalling to think that library developers would withhold access to standard POSIX 1003.1 features while they decide whether they approve of them. Donn ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] How to get a file path to the program invoked?
dokondr On the contrary, standard shell variable $0 - contains a full dokondr path to the program location in the directory structure, no dokondr matter from what directory the program was called. I don't think the comparison makes sense, as shell script invocation and executable run are very different mechanisms. Whenever you invoke a shell script, what really happens is that a program in your path (sh, bash ...) gets started with an argument that is the path to the script to load (your script actually). In this situation, you understand that it is easy to provide the path to the script (the $0) : it is just the file that the interpreter is loading. I don't know if it is possible at all to get this information in the context of binary execution. And I'm not sure it is a good practice anyway :) -- Paul ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] How to get a file path to the program invoked?
On 4/12/2011, at 7:32 PM, wren ng thornton wrote: Part of the problem is that, as Alexey says, the first element of argv is just whatever is passed to exec, which is not guaranteed to be a complete path, a canonical path, or any other specific thing we'd desire. It's not at all straightforward to determine the actual location of the executable, especially not in a platform-independent manner. argv[0] can't be trusted, scanning through $PATH isn't guaranteed to find it (and even if you find something of the right name, it's not guaranteed to be the correct executable), etc etc. In particular, with posix_spawnp(), the $PATH that is used to find the executable and the $PATH in the environment that the executable starts with can be two different things. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] How to get a file path to the program invoked?
It's not a poor practice at all. Example: gcc, which uses the executable's path as the base directory from which other files are located. MacOS also does something similar. -Original message- From: Paul R paul.r...@gmail.com To: dokondr doko...@gmail.com Cc: Simon Hengel simon.hen...@wiktory.org, haskell-cafe haskell-cafe@haskell.org Sent: Sun, Dec 4, 2011 15:26:28 PST Subject: Re: [Haskell-cafe] How to get a file path to the program invoked? dokondr On the contrary, standard shell variable $0 - contains a full dokondr path to the program location in the directory structure, no dokondr matter from what directory the program was called. I don't think the comparison makes sense, as shell script invocation and executable run are very different mechanisms. Whenever you invoke a shell script, what really happens is that a program in your path (sh, bash ...) gets started with an argument that is the path to the script to load (your script actually). In this situation, you understand that it is easy to provide the path to the script (the $0) : it is just the file that the interpreter is loading. I don't know if it is possible at all to get this information in the context of binary execution. And I'm not sure it is a good practice anyway :) -- Paul ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] How to get a file path to the program invoked?
That's true even for regular fork/exec. -Original message- From: Richard O'Keefe o...@cs.otago.ac.nz To: wren ng thornton w...@freegeek.org Cc: haskell-cafe haskell-cafe@haskell.org Sent: Sun, Dec 4, 2011 15:54:15 PST Subject: Re: [Haskell-cafe] How to get a file path to the program invoked? On 4/12/2011, at 7:32 PM, wren ng thornton wrote: Part of the problem is that, as Alexey says, the first element of argv is just whatever is passed to exec, which is not guaranteed to be a complete path, a canonical path, or any other specific thing we'd desire. It's not at all straightforward to determine the actual location of the executable, especially not in a platform-independent manner. argv[0] can't be trusted, scanning through $PATH isn't guaranteed to find it (and even if you find something of the right name, it's not guaranteed to be the correct executable), etc etc. In particular, with posix_spawnp(), the $PATH that is used to find the executable and the $PATH in the environment that the executable starts with can be two different things. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] How to get a file path to the program invoked?
On 12/1/11 11:12 AM, dokondr wrote: Hi, When my program starts it needs to know a complete path to the directory from which it was invoked. In terms of standard shell (sh) I need the Haskell function that will do equivalent to: #!/bin/sh path=$(dirname $0) That's not the path to the directory from which the script is invoked (aka, $PWD or, more accurately, the results of `pwd`). That's the path to the directory containing the script. The current working directory (the dir from which the program is invoked, provided the program haven't moved since invocation) can be gotten by System.Directory.getCurrentDirectory in the directory package. Getting the path to the location of the executable is trickier business. -- Live well, ~wren ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] How to get a file path to the program invoked?
On 12/1/11 2:26 PM, dokondr wrote: How to find this path using GHC libraries? There was a discussion about this recently over on libraries@, IIRC. The short answer is that, at present, there is no function to give you $0. We'd like to add such a function, but it's not been done yet. Part of the problem is that, as Alexey says, the first element of argv is just whatever is passed to exec, which is not guaranteed to be a complete path, a canonical path, or any other specific thing we'd desire. It's not at all straightforward to determine the actual location of the executable, especially not in a platform-independent manner. argv[0] can't be trusted, scanning through $PATH isn't guaranteed to find it (and even if you find something of the right name, it's not guaranteed to be the correct executable), etc etc. -- Live well, ~wren ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] How to get a file path to the program invoked?
Hi, When my program starts it needs to know a complete path to the directory from which it was invoked. In terms of standard shell (sh) I need the Haskell function that will do equivalent to: #!/bin/sh path=$(dirname $0) How to get this path in Haskell? getProgName :: IO String defined System.Environment only returns a file name of the program without its full path. Thanks! ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] How to get a file path to the program invoked?
How to get this path in Haskell? Maybe FindBin or executable-path work. Cheers, Simon ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] How to get a file path to the program invoked?
On Thu, Dec 1, 2011 at 2:12 PM, dokondr doko...@gmail.com wrote: Hi, When my program starts it needs to know a complete path to the directory from which it was invoked. In terms of standard shell (sh) I need the Haskell function that will do equivalent to: #!/bin/sh path=$(dirname $0) How to get this path in Haskell? If I understand you correctly, you want takeDirectory `fmap` getProgName where import System.FilePath (takeDirectory) Cheers, -- Felipe. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] How to get a file path to the program invoked?
How to get this path in Haskell? If I understand you correctly, you want takeDirectory `fmap` getProgName I think getProgName does not give you the full path, but only the program name. Cheers, Simon ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] How to get a file path to the program invoked?
On Thu, Dec 1, 2011 at 3:41 PM, Simon Hengel simon.hen...@wiktory.org wrote:
How to get this path in Haskell?
If I understand you correctly, you want
takeDirectory `fmap` getProgName
I think getProgName does not give you the full path, but only the
program name.
Neither does $0, does it? It depends on how the program is called.
You can always use System.Directory.getCurrentDirectory with
System.FilePath.{isRelative,replaceDirectory} if you somehow need the
full path. Note, however, that not even this is generally guaranteed
to be correct.
Cheers,
--
Felipe.
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Re: [Haskell-cafe] How to get a file path to the program invoked?
On Thu, Dec 01, 2011 at 03:53:37PM -0200, Felipe Almeida Lessa wrote: On Thu, Dec 1, 2011 at 3:41 PM, Simon Hengel simon.hen...@wiktory.org wrote: How to get this path in Haskell? If I understand you correctly, you want takeDirectory `fmap` getProgName I think getProgName does not give you the full path, but only the program name. Neither does $0, does it? It depends on how the program is called. $0 depend everything you need to find your program (say, the relative or absolute path used), but getProgName does not. Here is an example: ./foo/foo Here $0 will be ./foo/foo, but getProgName will be foo. Cheers, Simon ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] How to get a file path to the program invoked?
On Thu, Dec 01, 2011 at 07:02:09PM +0100, Simon Hengel wrote: On Thu, Dec 01, 2011 at 03:53:37PM -0200, Felipe Almeida Lessa wrote: On Thu, Dec 1, 2011 at 3:41 PM, Simon Hengel simon.hen...@wiktory.org wrote: How to get this path in Haskell? If I understand you correctly, you want takeDirectory `fmap` getProgName I think getProgName does not give you the full path, but only the program name. Neither does $0, does it? It depends on how the program is called. $0 depend everything you need to find your program (say, the relative or absolute path used), but getProgName does not. Here is an example: ./foo/foo Here $0 will be ./foo/foo, but getProgName will be foo. s/depend/contains ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] How to get a file path to the program invoked?
System.Directory.getCurrentDirectory does not solve the problem.
System.Directory.getCurrentDirectory returns the directory *from which* the
program was called, also called working directory.
The directory *from which* the program was called is not the same that the
directory *where the program executable is*, which my program needs to know.
For example:
/opt/myApp/test/myProg - is a program
One may call it in many ways:
1)
cd /opt/myApp/test/
./myProg
Current or working directory: ./
or:
2)
cd /usr/local
/opt/myApp/test/myProg
Current or working directory: /usr/local
On the contrary, standard shell variable $0 - contains a full path to the
program location in the directory structure, no matter from what directory
the program was called.
How to find this path using GHC libraries?
On Thu, Dec 1, 2011 at 8:53 PM, Felipe Almeida Lessa felipe.le...@gmail.com
wrote:
Neither does $0, does it? It depends on how the program is called.
You can always use System.Directory.getCurrentDirectory with
System.FilePath.{isRelative,replaceDirectory} if you somehow need the
full path. Note, however, that not even this is generally guaranteed
to be correct.
Cheers,
--
Felipe.
--
All the best,
Dmitri O. Kondratiev
This is what keeps me going: discovery
doko...@gmail.com
http://sites.google.com/site/dokondr/welcome
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Re: [Haskell-cafe] How to get a file path to the program invoked?
To be precise, $0 always contains the path to the program called. You are right, this path will change depending on location from which the program was called. So $0 is OK for my case, while current directory is unrelated. Try this: #!/bin/sh echo Arg 0: $0 echo All Parameters: [$@] Again, any way to get the same functionality in GHC? On Thu, Dec 1, 2011 at 10:32 PM, Giovanni Tirloni gtirl...@sysdroid.comwrote: On Thu, Dec 1, 2011 at 5:26 PM, dokondr doko...@gmail.com wrote: On the contrary, standard shell variable $0 - contains a full path to the program location in the directory structure, no matter from what directory the program was called. Are you sure? $ zero.sh ./zero.sh $ ./zero.sh ./zero.sh $ /home/gtirloni/zero.sh /home/gtirloni/zero.sh -- Giovanni ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] How to get a file path to the program invoked?
On Thu, Dec 1, 2011 at 14:26, dokondr doko...@gmail.com wrote: On the contrary, standard shell variable $0 - contains a full path to the program location in the directory structure, no matter from what directory the program was called If the shell found it by $PATH search, $0 will be simply the program name with no directory and you will have to repeat the PATH search yourself. (And the pathological case: the user did PATH=something yourprog, where something does not contain the directory holding yourprog.) There is no 100% reliable way to get the executable without using something like /proc/self/exe (only on Linux). -- brandon s allbery allber...@gmail.com wandering unix systems administrator (available) (412) 475-9364 vm/sms ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] How to get a file path to the program invoked?
dokondr doko...@gmail.com writes: Hi, When my program starts it needs to know a complete path to the directory from which it was invoked. In terms of standard shell (sh) I need the Haskell function that will do equivalent to: #!/bin/sh path=$(dirname $0) How to get this path in Haskell? getProgName :: IO String defined System.Environment only returns a file name of the program without its full path. Thanks! http://hackage.haskell.org/package/system-argv0-0.1 -- cheers! lelf xmpp:ni...@jabber.ru ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] How to get a file path to the program invoked?
On 01.12.2011 23:47, dokondr wrote:
To be precise, $0 always contains the path to the program called. You
are right, this path will change depending on location from which the
program was called. So $0 is OK for my case, while current directory is
unrelated.
Actually it contains whatever was passed to exec. By convention this is
program name but it could be anything
#include stdio.h
#include unistd.h
int main(int argc, char** argv)
{
if( argc != 1 ) {
printf(%i: %s\n, argc, argv[0] );
} else {
execl(./argv,Random junk,,0);
}
return 0;
}
$ gcc argv.c -o argv ./argv
2: Random junk
Try this:
#!/bin/sh
echo Arg 0: $0
echo All Parameters: [$@]
Again, any way to get the same functionality in GHC?
getArgs and getProgName should do the trick
http://hackage.haskell.org/packages/archive/base/latest/doc/html/System-Environment.html
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Re: [Haskell-cafe] How to get a file path to the program invoked?
Anton Nikishaev anton@gmail.com writes: dokondr doko...@gmail.com writes: Hi, When my program starts it needs to know a complete path to the directory from which it was invoked. In terms of standard shell (sh) I need the Haskell function that will do equivalent to: #!/bin/sh path=$(dirname $0) How to get this path in Haskell? getProgName :: IO String defined System.Environment only returns a file name of the program without its full path. Thanks! http://hackage.haskell.org/package/system-argv0-0.1 (which is argv[0], and surely it's not always the “complete path to the directory from which it was invoked”. $0 is not either.) -- lelf xmpp:ni...@jabber.ru ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] How to get a file path to the program invoked?
Balazs, thanks! It's great that these packages exist! On Thu, Dec 1, 2011 at 11:17 PM, Balazs Komuves bkomu...@gmail.com wrote: Hello, I'm not subscribed to haskell cafe, but I browse the archives sometimes. As Simon Hengel wrote there, there are two packages on Hackage trying to solve this exact problem (since GHC and the standard library does not provide the necessary information): http://hackage.haskell.org/package/executable-path http://hackage.haskell.org/package/FindBin (Hackage is down at the moment, so I'm not completely sure about the second link). I'm the author of the first one. Balazs ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
