Bug 1323

Summary: ssh-add: add an option to disable passphrase querying (batch mode)
Product: Portable OpenSSH Reporter: Vincent Lefevre <vincent-openssh>
Component: ssh-addAssignee: Assigned to nobody <unassigned-bugs>
Status: NEW ---    
Severity: enhancement CC: djm, vincent-openssh
Priority: P2    
Version: 4.6p1   
Hardware: Other   
OS: Other   

Description Vincent Lefevre 2007-06-19 18:51:22 AEST 
The ssh command has a BatchMode option to disable passphrase/password querying, but not ssh-add. Such an option would be useful so that identities without a passphrase could still be added without blocking a script (that is attached to a terminal for some reason).
Comment 1 Damien Miller 2014-07-07 18:09:56 AEST 
ssh-add < /dev/null ?
Comment 2 Vincent Lefevre 2014-07-07 19:08:48 AEST 
(In reply to Damien Miller from comment #1)
> ssh-add < /dev/null ?

The "< /dev/null" has no effect when $DISPLAY is NOT set:

$ env -u DISPLAY ssh-add < /dev/null
Enter passphrase for /home/vinc17/.ssh/id_rsa:

while it avoids that when DISPLAY is set:

$ ssh-add < /dev/null
ssh_askpass: exec(/usr/bin/ssh-askpass): No such file or directory

BTW, I don't know why I get such an error instead of a silent failure (note that $SSH_ASKPASS is not set). "ssh_askpass" is not documented in the ssh-add man page.

My machine is under Debian/unstable, with OpenSSH_6.6.1p1.