login shell or not?
In an interative shell, what is the easiest way to tell whether it is a login shell or not? Thanks. -- View this message in context: http://www.nabble.com/login-shell-or-not--tf3211932.html#a8919535 Sent from the Gnu - Bash mailing list archive at Nabble.com. ___ Bug-bash mailing list Bug-bash@gnu.org http://lists.gnu.org/mailman/listinfo/bug-bash
wrong lineno inside trap?
I wrote a test program test.sh: trap ' echo this is line 3, but LINENO=$LINENO ' 0 echo this is line 7, and LINENO=$LINENO --- when I ran it I got $ sh /tmp/test.sh this is line 7, and LINENO=7 this is line 3, but LINENO=11 My bash version is $ sh --version GNU bash, version 3.2.25(1)-release (x86_64-redhat-linux-gnu) Copyright (C) 2005 Free Software Foundation, Inc. Is this a known problem? Thanks. -- View this message in context: http://www.nabble.com/wrong-lineno-inside-trap--tp21383479p21383479.html Sent from the Gnu - Bash mailing list archive at Nabble.com.
Re: wrong lineno inside trap?
Chet Ramey wrote: > > > Bash-4.0 should behave better in this area, but quoted strings will > always cause unpredictable values for $LINENO. > > Chet > -- > ``The lyf so short, the craft so long to lerne.'' - Chaucer > > Chet Ramey, ITS, CWRUc...@case.edu > http://cnswww.cns.cwru.edu/~chet/ > > Thanks for the explanation. -- View this message in context: http://www.nabble.com/wrong-lineno-inside-trap--tp21383479p21472277.html Sent from the Gnu - Bash mailing list archive at Nabble.com.
ulimit and ssh?
Can someone explain this to me? Why am I not seeing correct results from ulimit after ssh into localhost? Thanks! $ ssh localhost bash -c 'ulimit -a' unlimited but $ bash -c 'ulimit -a' core file size (blocks, -c) 0 data seg size (kbytes, -d) unlimited scheduling priority (-e) 0 file size (blocks, -f) unlimited pending signals (-i) 32768 max locked memory (kbytes, -l) 32 max memory size (kbytes, -m) unlimited open files (-n) 1024 pipe size(512 bytes, -p) 8 POSIX message queues (bytes, -q) 819200 real-time priority (-r) 0 stack size (kbytes, -s) 10240 cpu time (seconds, -t) unlimited max user processes (-u) 1024 virtual memory (kbytes, -v) unlimited file locks (-x) unlimited -- View this message in context: http://www.nabble.com/ulimit-and-ssh--tp25262471p25262471.html Sent from the Gnu - Bash mailing list archive at Nabble.com.
Re: ulimit and ssh?
Bob, Thanks for the quick reply! A local unix guru also told me the same thing. So, just to make sure I really understand this, here is how I understand ssh worked: even thought I gave the command bash -c 'ulimit -a' as 3 separate strings, ssh (either the client or the server) actually concatenate them into one, and sshd forks a shell to parse the concatenated command string, in this case "bash -c ulimit -a".Correct me if I am wrong. Glad I learned something new. Bob Proulx wrote: > > peter360 wrote: >> Can someone explain this to me? Why am I not seeing correct results from >> ulimit after ssh into localhost? Thanks! >> >> $ ssh localhost bash -c 'ulimit -a' >> unlimited > > You have insufficiently quoted your argument to ssh. This is causing > bash not to get "ulimit -a" but to get "ulimit" "-a" instead. You are > seeing the output of "ulimit". > > Try this: > > ssh localhost "bash -c 'ulimit -a'" > > And this: > > echo ulimit -a | ssh localhost bash > > Bob > > > > -- View this message in context: http://www.nabble.com/ulimit-and-ssh--tp25262471p25263766.html Sent from the Gnu - Bash mailing list archive at Nabble.com.
Re: ulimit and ssh?
Bob, Thanks for the explanation. So my understanding of the way ssh works is still incorrect. I am confused about at which point the two parameters, "-c" and "ulimit -a" were converted into three, "-c", "ulimit", and "-a". I guess I need to read the source of ssh and bash to really understand this... Bob Proulx wrote: > > peter360 wrote: >> So, just to make sure I really understand this, here is how I understand >> ssh >> worked: even thought I gave the command bash -c 'ulimit -a' as 3 separate >> strings, > > Yes. > >> ssh (either the client or the server) actually concatenate them into >> one, > > No. It isn't put into one string unless you quote it as one string. > > -- View this message in context: http://www.nabble.com/ulimit-and-ssh--tp25262471p25351813.html Sent from the Gnu - Bash mailing list archive at Nabble.com.
Re: ulimit and ssh?
That makes sense. So the "feature" is to split all parameters on space even if they are quoted? I would vote to remove this "feature" in ssh. Thanks for the explanation. Greg Wooledge wrote: > > On Tue, Sep 08, 2009 at 11:39:02AM -0700, peter360 wrote: >> Thanks for the explanation. So my understanding of the way ssh works is >> still incorrect. I am confused about at which point the two parameters, >> "-c" and "ulimit -a" were converted into three, "-c", "ulimit", and "-a". >> I >> guess I need to read the source of ssh and bash to really understand >> this... > > It's an ssh "feature" for backward compatibility with remsh/rsh. > > imadev:~$ $HOME/bin/args 'ulimit -a' > 1 args: 'ulimit -a' > imadev:~$ remsh localhost $HOME/bin/args 'ulimit -a' > 2 args: 'ulimit' '-a' > imadev:~$ ssh localhost $HOME/bin/args 'ulimit -a' > wool...@localhost's password: > 2 args: 'ulimit' '-a' > > > > -- View this message in context: http://www.nabble.com/ulimit-and-ssh--tp25262471p25530173.html Sent from the Gnu - Bash mailing list archive at Nabble.com.
Re: ulimit and ssh?
In my case, I just got $ ssh localhost bash -x -c 'ulimit -a' unlimited + ulimit Not very informative. Marc Herbert-6 wrote: > > peter360 a écrit : > >> Thanks for the explanation. So my understanding of the way ssh works is >> still incorrect. I am confused about at which point the two parameters, >> "-c" and "ulimit -a" were converted into three, "-c", "ulimit", and "-a". >> I >> guess I need to read the source of ssh and bash to really understand >> this... > > Enabling tracing options usually helps a lot. > > > Instead of this: > sshlocalhost bash-c 'ulimit -a' > > Try this: > ssh -v localhost bash -x -c 'ulimit -a' > > > (And as usual, check out the "Guide to unix shell quoting") > > > > -- View this message in context: http://www.nabble.com/ulimit-and-ssh--tp25262471p25530174.html Sent from the Gnu - Bash mailing list archive at Nabble.com.
Re: ulimit and ssh?
Thanks Adreas. That was what I suspected in my reply to Bob. But Bob disagreed. Looks like there were some confusion about this feature even among experts. Seems another reason to deprecate the feature. -peter Andreas Schwab-2 wrote: > > peter360 writes: > >> That makes sense. So the "feature" is to split all parameters on space >> even >> if they are quoted? > > The feature is that ssh concatenates all remaining arguments to a single > string and passes that to the shell on the remote side. If you want to > preserve any quoting in this process you need to quote them. > > Andreas. > > -- > Andreas Schwab, sch...@linux-m68k.org > GPG Key fingerprint = 58CA 54C7 6D53 942B 1756 01D3 44D5 214B 8276 4ED5 > "And now for something completely different." > > > > -- View this message in context: http://www.nabble.com/ulimit-and-ssh--tp25262471p25754738.html Sent from the Gnu - Bash mailing list archive at Nabble.com.
Re: ulimit and ssh?
Thanks Bob. All the explanation were very helpful. Now I feel I have a good understanding of this little peculiarity of ssh. I agree with you that avoiding quoting altogether is simpler. But I am curious guy and learning for the sake of better understanding is also important to me. Bob Proulx wrote: > > peter360 wrote: >> Thanks Adreas. That was what I suspected in my reply to Bob. But Bob >> disagreed. Looks like there were some confusion about this feature even >> among experts. Seems another reason to deprecate the feature. > > I don't think anything I said disagreed with what Andreas said. It is > just confusing you since we are talking about different points in the > process. What does the local shell do, what does the ssh do, what > does the remote shell do, what is the end-to-end effect and so forth. > All three processes are handling the arguments and each has an affect > at different points in the timeline. I was talking end-to-end > (shell-ssh-shell) and Andreas was talking about ssh. > > And by the way but this feature can't really be changed or it would > break twenty years or so of scripts which rely upon the existing > behavior. > > Greg Wooledge wrote: >> imadev:~$ $HOME/bin/args 'ulimit -a' >> 1 args: 'ulimit -a' >> imadev:~$ remsh localhost $HOME/bin/args 'ulimit -a' >> 2 args: 'ulimit' '-a' >> imadev:~$ ssh localhost $HOME/bin/args 'ulimit -a' >> wool...@localhost's password: >> 2 args: 'ulimit' '-a' > > Nice! It would also be illustrative to show what happens without any > quoting and with quoting for two shell layers. > > $ $HOME/bin/show-args 'ulimit -a' > arg1: ulimit -a > > $ ssh -n localhost $HOME/bin/show-args ulimit -a > arg1: ulimit > arg2: -a > > $ ssh -n localhost $HOME/bin/show-args 'ulimit -a' > arg1: ulimit > arg2: -a > > $ ssh -n localhost $HOME/bin/show-args '"ulimit -a"' > arg1: ulimit -a > > Since there are two shells splitting words in the end-to-end result > then the effect is that you need to quote your arguments twice in > order to have an argument containing whitespace in one argument by the > time it has been processed through two shell's argument processing. > > Without sufficient quoting you have this following case, which isn't > what you want. The bash shell on the remote end would not see args > "-c" "ulimit -a" but would see "-a" as a separate > > $ ssh -n localhost $HOME/bin/show-args bash -c "ulimit -a" > arg1: bash > arg2: -c > arg3: ulimit > arg4: -a > > That isn't what you want. You need to quote the args twice. > > $ ssh -n localhost $HOME/bin/show-args 'bash -c "ulimit -a"' > arg1: bash > arg2: -c > arg3: ulimit -a > > In the end you want something like this: > > $ ssh -n localhost 'bash -c "ulimit -a"' > core file size (blocks, -c) 0 > data seg size (kbytes, -d) unlimited > scheduling priority (-e) 0 > file size (blocks, -f) unlimited > pending signals (-I) 8185 > max locked memory (kbytes, -l) 32 > max memory size (kbytes, -m) unlimited > open files (-n) 1024 > pipe size(512 bytes, -p) 8 > POSIX message queues (bytes, -q) 819200 > real-time priority (-r) 0 > stack size (kbytes, -s) 8192 > cpu time (seconds, -t) unlimited > max user processes (-u) 8185 > virtual memory (kbytes, -v) unlimited > file locks (-x) unlimited > > However I think it is simpler to avoid the argument processing and > instead using stdin to the shell. > > $ echo ulimit -a | ssh localhost bash > > Isn't that simpler? > > Bob > > > > -- View this message in context: http://old.nabble.com/ulimit-and-ssh--tp25262471p27086055.html Sent from the Gnu - Bash mailing list archive at Nabble.com.
