Sometimes when I run the shell scripts in Linux, It gives me error “: bad interpreter: No such file or directory”. The issue raised whenever I transfer my scripts from windows to Linux.
A Perl command can resolves the issue easily.
Try the following command on your text file then try and run it.
perl -i -pe’s/\r$//;’ <file name here>
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Tips & Tricks, Uncategorized | Tagged: bash | 
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Posted by jaymspatel
# # /etc/login.defs - Configuration control definitions for the login package. # # $Id: login.defs.linux,v 1.11 1999/08/27 19:02:50 marekm Exp $ # # Three items must be defined: MAIL_DIR, ENV_SUPATH, and ENV_PATH. # If unspecified, some arbitrary (and possibly incorrect) value will # be assumed. All other items are optional - if not specified then # the described action or option will be inhibited. # # Comment lines (lines beginning with "#") and blank lines are ignored. # # Modified for Linux. --marekm # # *REQUIRED* # Directory where mailboxes reside, _or_ name of file, relative to the # home directory. If you _do_ define both, MAIL_DIR takes precedence. # QMAIL_DIR is for Qmail (or any maildir-compatible MTA, such as Exim or # Postfix when suitably configured). # # Essentially, MAIL_DIR defines the $MAIL environmental variable # (for mbox use) by appending the username to MAIL_DIR as defined # below. MAIL_FILE defines the $MAIL environment variable as the # fully-qualified filename obtained by prepending the user home # directory before $MAIL_FILE, and QMAIL_DIR defines the MAIL # environment variable as the fully-qualified directory name # obtained by prepending the user home directory before $QMAIL_DIR. # # NOTE: This is used to setup your MAIL environment variable, and also # used by userdel to determine if any mail spools need to be removed when # removing a user. If you change this, you should also change the # pam_mail.so module setup in /etc/pam.d/login, which affects the "You # have mail" message on login, and, in default setup, overrides this setting # in determining the $MAIL environmental variable. # #QMAIL_DIR Maildir/ MAIL_DIR /var/mail #MAIL_FILE .mail # # Delay in seconds before being allowed another attempt after a login failure # FAIL_DELAY 3 # # Enable logging and display of /var/log/faillog login failure info. # FAILLOG_ENAB yes # # Enable display of unknown usernames when login failures are recorded. # LOG_UNKFAIL_ENAB no # # Enable logging of successful logins # LOG_OK_LOGINS no # # Enable setting of ulimit, umask, and niceness from passwd gecos field. # QUOTAS_ENAB yes # # Enable "syslog" logging of su activity - in addition to sulog file logging. # SYSLOG_SG_ENAB does the same for newgrp and sg. # SYSLOG_SU_ENAB yes SYSLOG_SG_ENAB yes # # If defined, all su activity is logged to this file. # #SULOG_FILE /var/log/sulog # # If defined, file which maps tty line to TERM environment parameter. # Each line of the file is in a format something like "vt100 tty01". # #TTYTYPE_FILE /etc/ttytype # # If defined, login failures will be logged here in a utmp format. # last, when invoked as lastb, will read /var/log/btmp, so... # FTMP_FILE /var/log/btmp # # If defined, the command name to display when running "su -". For # example, if this is defined as "su" then a "ps" will display the # command is "-su". If not defined, then "ps" would display the # name of the shell actually being run, e.g. something like "-sh". # SU_NAME su # # If defined, file which inhibits all the usual chatter during the login # sequence. If a full pathname, then hushed mode will be enabled if the # user's name or shell are found in the file. If not a full pathname, then # hushed mode will be enabled if the file exists in the user's home directory. # HUSHLOGIN_FILE .hushlogin #HUSHLOGIN_FILE /etc/hushlogins # # If defined, the presence of this value in an /etc/passwd "shell" field will # disable logins for that user, although "su" will still be allowed. # # XXX this does not seem to be implemented yet... --marekm # no, it was implemented but I ripped it out-- jfh NOLOGIN_STR NOLOGIN # # If defined, either a TZ environment parameter spec or the # fully-rooted pathname of a file containing such a spec. # #ENV_TZ TZ=CST6CDT #ENV_TZ /etc/tzname # # If defined, an HZ environment parameter spec. # # for Linux/x86 ENV_HZ HZ=100 # For Linux/Alpha... #ENV_HZ HZ=1024 # # *REQUIRED* The default PATH settings, for superuser and normal users. # # (they are minimal, add the rest in the shell startup files) ENV_SUPATH PATH=/sbin:/bin:/usr/sbin:/usr/bin:/usr/bin/X11:/usr/local/sbin:/usr/local/bin ENV_PATH PATH=/usr/local/bin:/usr/bin:/bin:/usr/bin/X11:/usr/games # # Terminal permissions # # TTYGROUP Login tty will be assigned this group ownership. # TTYPERM Login tty will be set to this permission. # # If you have a "write" program which is "setgid" to a special group # which owns the terminals, define TTYGROUP to the group number and # TTYPERM to 0620. Otherwise leave TTYGROUP commented out and assign # TTYPERM to either 622 or 600. # TTYGROUP tty TTYPERM 0600 # # Login configuration initializations: # # ERASECHAR Terminal ERASE character ('10' = backspace). # KILLCHAR Terminal KILL character ('25' = CTRL/U). # UMASK Default "umask" value. # ULIMIT Default "ulimit" value. # # The ERASECHAR and KILLCHAR are used only on System V machines. # The ULIMIT is used only if the system supports it. # (now it works with setrlimit too; ulimit is in 512-byte units) # # Prefix these values with "0" to get octal, "0x" to get hexadecimal. # ERASECHAR 0177 KILLCHAR 025 UMASK 022 #ULIMIT 2097152 # # Password aging controls: # # PASS_MAX_DAYS Maximum number of days a password may be used. # PASS_MIN_DAYS Minimum number of days allowed between password changes. # PASS_WARN_AGE Number of days warning given before a password expires. # PASS_MAX_DAYS 99999 PASS_MIN_DAYS 0 PASS_WARN_AGE 7 # # Min/max values for automatic uid selection in useradd # UID_MIN 1000 UID_MAX 60000 # # Min/max values for automatic gid selection in groupadd # GID_MIN 100 GID_MAX 60000 # # Max number of login retries if password is bad. This will most likely be # overriden by PAM, since the default pam_unix module has it's own built # in of 3 retries However, this is a safe fallback in case you are using # and authentication module that does not enforce PAM_MAXTRIES. # LOGIN_RETRIES 5 # # Max time in seconds for login # LOGIN_TIMEOUT 60 # # Number of significant characters in the password for crypt(). # Default is 8, don't change unless your crypt() is better. # If using MD5 in your PAM configuration, set this higher. # PASS_MAX_LEN 8 # # Require password before chfn/chsh can make any changes. # CHFN_AUTH yes # # Which fields may be changed by regular users using chfn - use # any combination of letters "frwh" (full name, room number, work # phone, home phone). If not defined, no changes are allowed. # For backward compatibility, "yes" = "rwh" and "no" = "frwh". # CHFN_RESTRICT rwh # # Password prompt (%s will be replaced by user name). # # XXX - it doesn't work correctly yet, for now leave it commented out # to use the default which is just "Password: ". #LOGIN_STRING "%s's Password: " # # Should login be allowed if we can't cd to the home directory? # Default in no. # DEFAULT_HOME yes # # If defined, this command is run when removing a user. # It should remove any at/cron/print jobs etc. owned by # the user to be removed (passed as the first argument). # #USERDEL_CMD /usr/sbin/userdel_local # # If defined, either full pathname of a file containing device names or # a ":" delimited list of device names. No password is required to log in # as a non-root user on these devices. # #NO_PASSWORD_CONSOLE tty1:tty2:tty3:tty4:tty5:tty6 # # When prompting for password without echo, getpass() can optionally # display a random number (in the range 1 to GETPASS_ASTERISKS) of '*' # characters for each character typed. This feature is designed to # confuse people looking over your shoulder when you enter a password
. # Also, the new getpass() accepts both Backspace (8) and Delete (127) # keys to delete previous character (to cope with different terminal # types), Control-U to delete all characters, and beeps when there are # no more characters to delete, or too many characters entered. # # Setting GETPASS_ASTERISKS to 1 results in more traditional behaviour - # exactly one '*' displayed for each character typed. # # Setting GETPASS_ASTERISKS to 0 disables the '*' characters (Backspace, # Delete, Control-U and beep continue to work as described above). # # Setting GETPASS_ASTERISKS to -1 reverts to the traditional getpass() # without any new features. This is the default. # #GETPASS_ASTERISKS 1 # # Enable setting of the umask group bits to be the same as owner bits # (examples: 022 -> 002, 077 -> 007) for non-root users, if the uid is # the same as gid, and username is the same as the primary group name. # # This also enables userdel to remove user groups if no members exist. # USERGROUPS_ENAB yes # # Instead of the real user shell, the program specified by this parameter # will be launched, although its visible name (argv[0]) will be the shell's. # The program may do whatever it wants (logging, additional authentification, # banner, ...) before running the actual shell. # # FAKE_SHELL /bin/fakeshell # # Enable pam_close_session() calling. When using normal (pam_unix.so) # session handling modules, this is not needed. However with modules # (such as kerberos or other persistent session models), login and su # need to fork and wait for the shell to exit so that sessions can be # cleaned up. # #CLOSE_SESSIONS no ################# OBSOLETED BY PAM ############## # # # These options are now handled by PAM. Please # # edit the appropriate file in /etc/pam.d/ to # # enable the equivelants of them. # ############### #MOTD_FILE #DIALUPS_CHECK_ENAB #LASTLOG_ENAB #MAIL_CHECK_ENAB #OBSCURE_CHECKS_ENAB #PORTTIME_CHECKS_ENAB #CONSOLE #SU_WHEEL_ONLY #CRACKLIB_DICTPATH #PASS_CHANGE_TRIES #PASS_ALWAYS_WARN #MD5_CRYPT_ENAB #CONSOLE_GROUPS #ENVIRON_FILE #NOLOGINS_FILE #ISSUE_FILE #PASS_MIN_LEN
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Linux, Tips & Tricks | Tagged: login.defs | 
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Posted by jaymspatel
E1 is a standard for a digital telecommunications links is widely used within Europe. It enables the transmission of several (multiplexed) voice/data channels simultaneously on the same transmission facility. More specifically it has an overall bandwidth of 2048 kbps and provides 32 channels each supporting a data rate of 64 kbps. The lines are mainly used to connect between the PABX (Private Automatic Branch eXchange), and the CO (Central Office) or main exchange.
The E1 standard defines the physical characteristics of a transmission path, and as such it corresponds to the physical layer (layer 1) in the OSI model. Technologies such as ATM and others which form layer 2 are able to pass over E1 lines, making E1 one of the fundamental technologies used within telecommunications.
A similar standard to E1, known as T1 has similar characteristics, but it is widely used in North America. Often equipment used for these technologies, e.g. test equipment may be used for both, and the abbreviation E1/T1 may be seen.
E1 beginnings
Development The life of the standards started back in the early 1960s when Bell Laboratories, where the transistor was invented some years earlier, developed a voice multiplexing system to enable better use to be made of the lines that were required, and to provide improved performance of the analogue techniques that were used. The step of the process converted the signal into a digital format having a 64 kbps data stream. The next stage is to assemble twenty four of the data streams into a framed data stream with an overall data rate of 1.544 Mbps. This structured signal was called DS1, but it is almost universally referred to as T1.
In Europe, the basic scheme was taken by what was then the CCIT and developed to fit the European requirements better. This resulted in the development of the scheme known as E1. This has provision for 30 voice channels and runs at an overall data rate of 2.048 Mbps. In Europe E1 refers to both the formatted version and the raw data rate.
E1 Applications and standards
The E-carrier standards form part of the overall Synchronous Digital Hierarchy (SDH) scheme. This allows where groups of E1 circuits, each containing 30 circuits, to be combined to produce higher capacity. E1 to E5 are defined and they are carriers in increasing multiples of the E1 format. However in reality only E3 is widely used and this can carry 480 circuits and has an overall capacity of 34.368 Mbps.
Physically E1 is transmitted as 32 timeslots and E3 has 512 timeslots. Unlike Internet data services which are IP based, E-carrier systems are circuit switched and permanently allocate capacity for a voice call for its entire duration. This ensures high call quality because the transmission arrives with the same short delay (Latency) and capacity at all times. Nevertheless it does not allow the same flexibility and efficiency to be obtained as that of an IP based system.
In view of the different capacities of E1 and E3 links they are used for different applications. E1 circuits are widely used to connect to medium and large companies, to telephone exchanges. They may also be used to provide links between some exchanges. E3 lines are used where higher capacity is needed. They are often installed between exchanges, and to provide connectivity between countries.
E1 description
An E1 link runs over two sets of wires that are normally coaxial cable and the signal itself comprises a nominal 2.4 volt signal. The signalling data rate is 2.048 Mbps full duplex and provides the full data rate in both directions.
For E1, the signal is split into 32 channels each of 8 bits. These channels have their own time division multiplexed slots. These are transmitted sequentially and the complete transmission of the 32 slots makes up a frame. These Time Slots are nominated TS0 to TS31 and they are allocated to different purposes:
Time slot 0 is reserved for framing purposes, and alternately transmits a fixed pattern. This allows the receiver to lock onto the start of each frame and match up each channel in turn. The standards allow for a full Cyclic Redundancy Check to be performed across all bits transmitted in each frame.
E1 signalling data is carried on TS16 is reserved for signalling, including control, call setup and teardown. These are accomplished using standard protocols including Channel Associated Signalling (CAS) where a set of bits is used to replicate opening and closing the circuit. Tone signalling may also be used and this is passed through on the voice circuits themselves. More recent systems use Common Channel Signalling (CCS) such as ISDN or Signalling System 7 (SS7) which sends short encoded messages containing call information such as the caller ID.
Several options are specified in the original CEPT standard for the physical transmission of data. However an option or standard known as HDB3 (High-Density Bipolar-3 zeros) is used almost exclusively.
Future
E1 and also T1 are well established for telecommunications use. However with new technologies such as ADSL, DSL, and the other IP based systems that are now being widely deployed, these will spell the end of E1 and T1. Nevertheless they have given good service over many years, and they will remain in use as a result of this wide deployment for some years to come.
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Tips & Tricks | Tagged: Networking | 
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Posted by jaymspatel
Good Tutorial for find command’s exercise.
http://www.linuxquestions.org/linux/answers/Applications_GUI_Multimedia/Find_command_0
http://www.linux.ie/newusers/beginners-linux-guide/find.php
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Posted by jaymspatel
