01-31-2003
passwd opens /dev/tty for reading. And it will read /dev/tty to obtain a password. Before it reads the terminal, it reconfigures it to turn off echo, so that the password cannot be seen as it is typed. If that reconfiguration fails, passwd will give up. And after it has the password, it turns echo back on. Operations like these simply require a terminal.
If that behavior is acceptable, then the passwd command does indeed work in scripts just fine. The "problem" is that people want the script to be able to supply the password rather than the user of the script. In that case, you need expect.
10 More Discussions You Might Find Interesting
1. UNIX for Dummies Questions & Answers
Hello All,
I am working on Sco unix version 5.0.5.
The passwd command has somehow got corrupted and is only displaying the contents of the /etc/passwd file instead of changing the password.
I wanted to know if there is any other command through which you can change the password of a user from... (5 Replies)
Discussion started by: rahulrathod
5 Replies
2. Shell Programming and Scripting
-----------------------------------------------------------------------------Pls find my Q in the bottom---------------------------------------------
#!/bin/ksh
#+----------------------------------------------
#|
#| Usage: . scripts/run_all.ksh < scripts/run_all.txt
#|
#| This script... (2 Replies)
Discussion started by: thumsup9
2 Replies
3. Shell Programming and Scripting
As extracting of the file /etc/passwd the IDīs that have not been used in a range specifies. (2 Replies)
Discussion started by: oscar_acm
2 Replies
4. UNIX for Dummies Questions & Answers
hi all,
i was given by my supervisor a task to search for scripts which contain oracle sqlplus i.e "myusername/mypasswd @myDB" in every /home/userfolder, which are, all the scripts made by different user. I've done some find command to search string for sqlplus, but it may up too long to respond.... (8 Replies)
Discussion started by: Helmi
8 Replies
5. Shell Programming and Scripting
I am using Ubuntu linux desktop, and I am trying to schedule a sheel script to run every 10minutes.
These are the steps I have taken:
crontab -e
added and saved this line to the file
# m h dom mon dow command
*/1 * * * * /home/enzo/Desktop/dlrecentuse
restarted cron:
sudo... (5 Replies)
Discussion started by: daydreamer
5 Replies
6. UNIX for Dummies Questions & Answers
on Runnning passwd command on HPUX 11.23
I am getting
pam_chauthtok: Shared object load failure.
Pls help ... (1 Reply)
Discussion started by: ultimatix
1 Replies
7. Red Hat
how unix users able to change their password even if they have only read permissions and how backend process will be happening can u explain me which are files need to involved in this process (3 Replies)
Discussion started by: ponmuthu
3 Replies
8. Solaris
Hi all,
I have got a problem,
i have Solaris 8 server, where on running the passwd command, it says permission denied. I have checked /bin/passwd, /etc/passwd, /etc/shadow all have permissions as like one working server.
It is happening for root user and all other users.
i have tried... (6 Replies)
Discussion started by: varunksharma87
6 Replies
9. Shell Programming and Scripting
I am trying to add some code to the begging of a script so that it will remove all the .transcript files, when their is no coressponding .wav file. But it doesnt work.
This is the code I have added:
for transcriptfile in `$voicemaildir/*.transcript`; do
wavfile=`echo $transcriptfile | cut -d'.'... (2 Replies)
Discussion started by: ghurty
2 Replies
10. Shell Programming and Scripting
I have a file "file1" that contains several ip address , and the "file2" contains several records , each line in file2 contains somewhere the ip address that i am searching in the file1
I use the unix command grep -w
for i in `cat file1`
do
grep -w "$i" file2 >> file3
done
... (9 Replies)
Discussion started by: knijjar
9 Replies
LEARN ABOUT REDHAT
getpass
GETPASS(3) Linux Programmer's Manual GETPASS(3)
NAME
getpass - get a password
SYNOPSIS
#include <unistd.h>
char *getpass( const char * prompt );
DESCRIPTION
This function is obsolete. Do not use it.
The getpass() function opens /dev/tty (the controlling terminal of the process), outputs the string prompt, turns off echoing, reads one
line (the "password"), restores the terminal state and closes /dev/tty again.
RETURN VALUE
The function getpass returns a pointer to a static buffer containing the (first PASS_MAX bytes of) the password without the trailing new-
line, terminated by a NUL. This buffer may be overwritten by a following call. On error, the terminal state is restored, errno is set
appropriately, and NULL is returned.
ERRORS
The function may fail if
ENXIO The process does not have a controlling terminal.
NOTES
For libc4 and libc5, the prompt is not written to /dev/tty but to stderr. Moreover, if /dev/tty cannot be opened, the password is read
from stdin. The static buffer has length 128 so that only the first 127 bytes of the password are returned. While reading the password,
signal generation (SIGINT, SIGQUIT, SIGSTOP, SIGTSTOP) is disabled and the corresponding characters (usually control-C, control-, control-
Z and control-Y) are transmitted as part of the password. Since libc 5.4.19 also line editing is disabled, so that also backspace and the
like will be seen as part of the password.
For glibc2, if /dev/tty cannot be opened, the prompt is written to stderr and the password is read from stdin. There is no limit on the
length of the password. Line editing is not disabled.
According to the SUSv2, the value of PASS_MAX must be defined in <limits.h> in case it is smaller than 8, and can in any case be obtained
using sysconf(_SC_PASS_MAX). However, POSIX.2 withdraws the constants PASS_MAX and _SC_PASS_MAX, and the function getpass (). Libc4 and
libc5 have never supported PASS_MAX or _SC_PASS_MAX. Glibc2 accepts _SC_PASS_MAX and returns BUFSIZ (e.g., 8192).
FILES
/dev/tty
SEE ALSO
crypt(3)
HISTORY
A getpass function appeared in Version 7 AT&T UNIX.
BUGS
The calling process should zero the password as soon as possible to avoid leaving the cleartext password visible in the process's address
space.
Linux Manpage 2000-12-05 GETPASS(3)