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Linux and pipes
Posted: Tue Apr 29, 2025 8:11 pm
by kake26
In Linux on occasion one might want to pipe the output of one command to another then do something with the output. However, it seems purebasic via the run command doesn't work as I'd expect. I'm sure there some nuance I'm missing, I just can't figure it. I've resolved my problem with find a single command to do the job and that workeds.
Here is a example of the code that behaves odd.
Code: Select all
fndver = RunProgram("dpkg", "-l discord | awk '/discord/{print $3}'", "", #PB_Program_Open | #PB_Program_Read | #PB_Program_Error | #PB_Program_Hide)
If fndver
While ProgramRunning(fndver) And (ElapsedMilliseconds() - StartTime < Timeout)
If AvailableProgramOutput(fndver)
Output$ + ReadProgramString(fndver)
EndIf
If AvailableProgramError(fndver)
Error$ + ReadProgramError(fndver)
EndIf
Delay(10)
Wend
If ProgramRunning(fndver)
KillProgram(fndver)
Output$ = "Error: Command timed out"
EndIf
CloseProgram(fndver)
EndIf
Debug "Error Output: " + Error$
What I expect is to get a output like
$ dpkg -l discord | awk '/discord/{print $3}'
0.0.92
I know its because I'm overlooking something, but what that is it eludes me. Would someone please shed some light on this?
Just for reference the output I get is more like this.
Discord version: Desired=Unknown/Install/Remove/Purge/Hold| Status=Not/Inst/Conf-files/Unpacked/halF-conf/Half-inst/trig-aWait/Trig-pend|/ Err?=(none)/Reinst-required (Status,Err: uppercase=bad)||/ Name Version Architecture Description+++-==============-============-============-=================================un awk <none> <none> (no description available)ii grep 3.7-1build1 amd64 GNU grep, egrep and fgrep
Yeah totally not the expected.
Re: Linux and pipes
Posted: Fri May 02, 2025 7:33 pm
by benubi
Perhaps you also need the #PB_Program_Connect flag
Re: Linux and pipes
Posted: Fri May 02, 2025 11:04 pm
by Piero
AvailableProgramError is not PB…
If you need single/double quotes, pipes etc.:
Code: Select all
Procedure simpleShell(ShellCommand$, wait = #False)
Protected shell = RunProgram("/bin/sh","","", #PB_Program_Open|#PB_Program_Write)
If shell
WriteProgramStringN(shell,ShellCommand$)
WriteProgramData(shell,#PB_Program_Eof,0)
If wait
While ProgramRunning(shell) : Delay(10) : Wend
EndIf
CloseProgram(shell)
EndIf
EndProcedure
Structure daResults : Out.s : Err.s : ExC.w : EndStructure
Global Sh.daResults
Procedure Shell(ShellCommand$, AddLF = #True)
Protected Err$, tmper$, Output$, shell, Exc.w =-1 ; exit code -1 on failed launch
shell = RunProgram("/bin/sh","","",
#PB_Program_Open|#PB_Program_Write|#PB_Program_Read|#PB_Program_Error )
If shell
WriteProgramStringN(shell,ShellCommand$)
WriteProgramData(shell,#PB_Program_Eof,0)
While ProgramRunning(shell)
If AvailableProgramOutput(shell)
Output$ + ReadProgramString(shell)
If AddLF : Output$ + ~"\n" : EndIf
EndIf
tmper$ = ReadProgramError(shell)
If tmper$ : Err$ + tmper$ + ~"\n" : EndIf
Wend
Exc = ProgramExitCode(shell) : CloseProgram(shell)
EndIf
Sh\Out = Output$ : Sh\Err = Err$ : Sh\ExC = Exc
EndProcedure
Procedure.s QuoteString(str$) ; useful to quote FILE/FOLDER PATHS
ProcedureReturn "'" + ReplaceString(str$, "'", "'\''") + "'"
EndProcedure
Shell(~"echo '\"a\" 'b")
Debug Sh\Out
Re: Linux and pipes
Posted: Sat May 03, 2025 11:41 am
by NicTheQuick
You need a shell to be able to use pipes. RunProgram does not spawn a shell. It runs a command with arguments/parameters.
In principle it should work like this:
Code: Select all
program = RunProgram("/bin/sh", "-c 'whoami | md5sum'", "", #PB_Program_Open | #PB_Program_Read)
Output$ = ""
If program
While ProgramRunning(program)
If AvailableProgramOutput(program)
Output$ + ReadProgramError(program) + #LF$
Output$ + ReadProgramString(program) + #LF$
EndIf
Wend
Output$ + #LF$
Output$ + "Exitcode: " + Str(ProgramExitCode(program))
CloseProgram(program)
EndIf
MessageRequester("Output", Output$)
But somehow I only see Exitcode 2. The code is a modified version of that one from the help page of `RunProgram`.
Re: Linux and pipes
Posted: Sat May 03, 2025 1:10 pm
by Piero
NicTheQuick wrote:
Code: Select all
RunProgram("/bin/sh", "-c 'whoami | md5sum'"…
Code: Select all
Shell("sh -lc " + QuoteString("whoami | md5sum…") ; QuoteString and Shell posted above
Re: Linux and pipes
Posted: Sat May 03, 2025 1:19 pm
by Axolotl
Acc. to the Help Pages, there is a small difference between this procedures:
Code: Select all
ReadProgramError() ; non blocking <=> ... doesn't halt the program flow if no error output is available
ReadProgramString() and ReadProgramData() ; blocking <=> ... waits until there is data available to read from the program
which means the code should look like this.....
Code: Select all
;....
Output$ + ReadProgramError(program) + #LF$
If AvailableProgramOutput(program)
Output$ + ReadProgramString(program) + #LF$
EndIf
;.....
Re: Linux and pipes
Posted: Sat May 03, 2025 1:27 pm
by Piero
Axolotl wrote: Sat May 03, 2025 1:19 pm
Output$ + ReadProgramError(program) + #LF$
If AvailableProgramOutput(program)
Output$ + ReadProgramString(program) + #LF$
EndIf
No: Output$ is not for ProgramError
Re: Linux and pipes
Posted: Sat May 03, 2025 1:41 pm
by NicTheQuick
Oh, I see. I need double quotes and not single quotes.
Code: Select all
program = RunProgram("/bin/sh", ~"-c \"/bin/whoami | /bin/md5sum\"", "", #PB_Program_Open | #PB_Program_Read)
But why do I get an "Invalid memory access" on `ReadProgramError()`? That looks like a weird bug. Maybe I should check the beta versions if that got fixed already.
Re: Linux and pipes
Posted: Sat May 03, 2025 3:27 pm
by Piero
NicTheQuick wrote: Sat May 03, 2025 1:41 pm
Oh, I see. I need double quotes and not single quotes.
Code: Select all
program = RunProgram("/bin/sh", ~"-c \"/bin/whoami | /bin/md5sum\"", "", #PB_Program_Open | #PB_Program_Read)
But why do I get an "Invalid memory access" on `ReadProgramError()`? That looks like a weird bug. Maybe I should check the beta versions if that got fixed already.
You made me remember the 1st time I tried to fight with runprogram on Mac……… forget the "bugs"…
IT'S BECAUSE YOU DON'T USE (the above) SHELL() !!!
Code: Select all
#PB_Program_Open|#PB_Program_Write|#PB_Program_Read|#PB_Program_Error
WriteProgramStringN(shell,ShellCommand$)
WriteProgramData(shell,#PB_Program_Eof,0)
Re: Linux and pipes
Posted: Sat May 03, 2025 4:55 pm
by Piero
Re: Linux and pipes
Posted: Sun May 04, 2025 2:02 am
by kake26
Okay, thank you. I figured it was something like that. No shell spawned go it. Now that I know that I can find a way to make it work. Thanks again.
Runprogram Shell Summary (quote pipe etc.)
Posted: Tue Jul 15, 2025 12:21 am
by Piero
may potentially produce a ton of unneeded LineFeeds! (~"\n" = #LF$)
From the Shell() Procedure posted above:
Code: Select all
tmper$ = ReadProgramError(shell)
If tmper$ : Err$ + tmper$ + ~"\n" : EndIf ; If tmper$ <> "" …
Note: needs #PB_Program_Error
How to merge out and err:
Code: Select all
Shell("hgfhjf")
Debug Sh\Err
Debug "--------------"
Shell("hgfhjf 2>&1") ; stderr to stdout
Debug Sh\Out
Debug "--------------"
This part is to use "pipes and quotes" as you would do on terminal:
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WriteProgramStringN(shell,ShellCommand$)
WriteProgramData(shell,#PB_Program_Eof,0)
Note: needs #PB_Program_Write
This will be a login shell like a terminal (e.g., will "see" stuff added to ~/.profile):
Code: Select all
ls$= ~"shopt -q login_shell && echo 'Login shell' || echo 'Not login shell' \n echo End" ; ~"\n" or ; ? ;)
Shell("sh -lc " + QuoteString(ls$) ) ; better ALWAYS use QuoteString for -c
Debug Sh\Out
Debug "--------------"
You can also do this way:
Code: Select all
shell = RunProgram("/bin/sh", "-l", …
Recent MacOS Terminal uses zsh (and ~/.zprofile)
If you need to "send scripts" or use multiple commands,
TEST HOW YOUR SHELL BEHAVES FROM PB! (better ; or \n ?)
Also:
