Login or Register to Ask a Question and Join Our Community


Shell Programming and Scripting

ssh and redirection

Login to Discuss or Reply to this Discussion in Our Community

 
Thread Tools Search this Thread
Top Forums Shell Programming and Scripting ssh and redirection
# 8  
Old 10-06-2011
thanks for your perseverance !

the command is ok but it does nothing at all , surprising !

Code:
# ssh -t newuser@server  "sudo -u user1 echo -n /var/spool/mail/user1"

Code:
# ssh -t newuser@server  "sudo -u user1 ls -al /var/spool/mail/user1" 
-rw-rw-r-- 1 user1 mail 804915 Oct  6 16:13 /var/spool/mail/user1

the file is still full

regards
Christian
# 9  
Old 10-06-2011
Code:
ssh -t newuser@server  "sudo -u user1 cp /dev/null /var/spool/mail/user1"

Might work
# 10  
Old 10-06-2011
That may delete and recreate the file and leave the old file still open hogging disk, unfixable without rebooting the daemon or server! Don't do it!

---------- Post updated at 08:38 AM ---------- Previous update was at 08:36 AM ----------

The reason none of the commands using redirection worked is that the redirection happens before the su. So you don't get permission to truncate the file.

To get permissions to run the file, the command to truncate the file will need to run in a shell with permissions to do so.

Try this:

Code:
echo ": > /var/spool/mail/user1" | ssh -t newuser@server sudo -u user1 /bin/sh

This should run : > /var/spool/mail/user1 in a shell belonging to user1.
This User Gave Thanks to Corona688 For This Post:
CarloM
# 11  
Old 10-06-2011
Well the "cp /dev/null" is ok but seems to be dangerous...

and the last solution gives this result

Quote:
Pseudo-terminal will not be allocated because stdin is not a terminal.
sudo: no tty present and no askpass program specified
thanks for your help

Christian
# 12  
Old 10-06-2011
Quote:
Originally Posted by Nicol
thanks for your perseverance !

the command is ok but it does nothing at all , surprising !

Code:
# ssh -t newuser@server  "sudo -u user1 echo -n /var/spool/mail/user1"

Code:
# ssh -t newuser@server  "sudo -u user1 ls -al /var/spool/mail/user1" 
-rw-rw-r-- 1 user1 mail 804915 Oct  6 16:13 /var/spool/mail/user1

the file is still full

regards
Christian
where is redirection sign?
Code:
# ssh -t newuser@server  "sudo -u user1 echo -n > /var/spool/mail/user1"

# 13  
Old 10-06-2011
same result with the ">"

regards
Christian
# 14  
Old 10-06-2011
Putting that in quotes instead of quote tags means when I try and quote you, the error message disappears. Use code tags for code.

"no askpass program" means it needs to ask you for a password and can't because it's not in a terminal. Run it in a terminal.

---------- Post updated at 09:12 AM ---------- Previous update was at 09:11 AM ----------

Quote:
Originally Posted by ygemici
where is redirection sign?
Code:
# ssh -t newuser@server  "sudo -u user1 echo -n > /var/spool/mail/user1"

This won't work, again, because the redirection happens before the sudo. The shell doesn't have permissions to overwrite the file, and will fail to redirect into it.

---------- Post updated at 09:14 AM ---------- Previous update was at 09:12 AM ----------

Perhaps:

Code:
ssh -t newuser@server echo "': > /var/spool/mail/user1'" '|' sudo -u user1 /bin/sh
Login or Register to Ask a Question

Previous Thread | Next Thread

9 More Discussions You Might Find Interesting

1. UNIX for Beginners Questions & Answers

Ssh script to validate ssh connection to multiple serves with status

Hi, I want to validate ssh connection one after one for multiple servers..... password less keys already setup but now i want to validate if ssh is working fine or not... I have .sh script like below and i have servers.txt contains all the list of servers #/bin/bash for host in $(cat... (3 Replies)
Discussion started by: sreeram4
3 Replies

2. Shell Programming and Scripting

SSH file redirection is not maintaining format

Hi, I'm running a script which would ssh to various ssh-trust enabled servers and get a list of packages installed. The output of this command would be redirected to a file ssh -q $i 'rpm -qa --queryformat '%{NAME}\t\t,%{ARCH}\t\t,%{VERSION}-%{RELEASE}\t\t,%{INSTALLTIME:date}\n'|sed... (2 Replies)
Discussion started by: maverick_here
2 Replies

3. UNIX for Dummies Questions & Answers

about different redirection

explain the redirections 1>, 2>, 3>, ..... and 1< ,2<,3<..... where we use these things thanks Thread moved from AIX forum (2 Replies)
Discussion started by: tsurendra
2 Replies

4. Shell Programming and Scripting

Redirection

Hello All, I am using the below script to gather various tools running by the user, we have more than 100 tools running on the server so my challenge is to redirect memory & cpu load to the file with the name of the tool.so am using the below script i am stucking how to redirect to the file... (2 Replies)
Discussion started by: ajaincv
2 Replies

5. Shell Programming and Scripting

I/O redirection

Hello everyone,I'm reading a book and there's code fragment: exec 3>&1 ls -l 2>&1 >&3 3>&- | grep bad 3>&- exec 3>&- It says that the red part of that code does not close fd 3 but the green does close the fd 3.I can't understand that.....Why?Any predicate will be appreciated.:) (18 Replies)
Discussion started by: homeboy
18 Replies

6. Shell Programming and Scripting

Double redirection

Hi to all. It's possible with a single line redirect to stdout and to a file a echoed string? I need something like this: echo "Pizza" >/tmp/file (and same time print to stout "Pizza")... What can i do? (2 Replies)
Discussion started by: mendez
2 Replies

7. UNIX for Dummies Questions & Answers

Help with Redirection

Hi Guys, I m new to UNIX and new to this forum. Was wondering if someone can help me understand redirection (standard input output pipeline etc) for starters, not too sure what this would mean who | sort > sortedfile | pr | lp im starting to understand common commands but when throwing... (2 Replies)
Discussion started by: jmack123
2 Replies

8. Shell Programming and Scripting

redirection

Hi, The code below works, it's a part of a bash shell script that serve to search a pattern $pattern_da_cercare in the files contained in a directory $directory_iniziale. Now the proble is: How can I redirect stderr to a file? PS: so I want to redirect ALL the errors to a file. I tryed... (9 Replies)
Discussion started by: DNAx86
9 Replies

9. Programming

Help with redirection

Here is my problem. I don't know make this redirection thing work. The output file (called output.c) looks like this #include<stdio.h> int main() { int k; int m; print f("%d\n", k); printf("%d\n", m); return 0; } the input file(called input.c) is this #include<stdio.h> int... (2 Replies)
Discussion started by: Shallon1
2 Replies
Login or Register to Ask a Question