Sanjeev Sabhlok's notes on technology, hardware, gardening

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UNIX commands. UNIX refresher. UNIX key commands

My google document on UNIX here.


find all files after a date: 

#Create an empty file based on date you are looking for, following format is: YYYYMMDDhhmm

touch -t 200609010001 testfile

find . -newer testfile >list

Unix scripting

First, understand that Unix doesn't need ".bat" or any other extension. You can call it myfile.bat if that makes you warm and fuzzy, but you don't need to. Unix will execute a file if its permissions include the "execute" bit. So, to create a script file that contains commands you want to run:

Create the file. You can use the GUI Text Editor, vi (see VI Primer) or even something as simple as this:

cat > myscript

(type your commands)

(as many lines as you want)

(end with CTRL-D on a line by itself)

The file needs to be marked executable- if everyone should be able to run it, do:

chmod 755 myscript

If the script is placed in a directory included in your PATH (see Why can't I run this program? above), typing "myscript" will now run those commands.


Copied from the internet for my personal convenience. 

  • cat — for creating and displaying short files
  • chmod — change permissions
  • cd — change directory
  • cp — for copying files
  • date — display date
  • echo — echo argument
  • ftp — connect to a remote machine to download or upload files
  • grep — search file
  • head — display first part of file
  • ls — see what files you have
  • lpr — standard print command (see also print )
  • more — use to read files
  • mkdir — create directory
  • mv — for moving and renaming files
  • ncftp — especially good for downloading files via anonymous ftp.
  • print — custom print command (see also lpr )
  • pwd — find out what directory you are in
  • rm — remove a file
  • rmdir — remove directory
  • rsh — remote shell
  • setenv — set an environment variable
  • sort — sort file
  • tail — display last part of file
  • tar — create an archive, add or extract files
  • telnet — log in to another machine
  • wc — count characters, words, lines

login: `Logging in'
ssh: Connect to another machine
logout: `Logging out'

File Management

emacs: `Using the emacs text editor'
mkdir: `Creating a directory'
cd: `Changing your current working directory'
ls: `Finding out what files you have'
cp: `Making a copy of a file'
mv: `Changing the name of a file'
rm: `Getting rid of unwanted files'
chmod: `Controlling access to your files'
cmp: Comparing two files
wc: Word, line, and character count
compress: Compress a file


e-mail: `Sending and receiving electronic mail'
talk: Talk to another user
write: Write messages to another user
sftp: Secure file transfer protocol


man: Manual pages
quota -v: Finding out your available disk space quota
ical: `Using the Ical personal organizer'
finger: Getting information about a user
passwd: Changing your password
who: Finding out who's logged on


lpr: `Printing'
lprm: Removing a print job
lpq: Checking the print queues



  • ls — lists your files 
    ls -l — lists your files in 'long format', which contains lots of useful information, e.g. the exact size of the file, who owns the file and who has the right to look at it, and when it was last modified. 
    ls -a — lists all files, including the ones whose filenames begin in a dot, which you do not always want to see. 
    There are many more options, for example to list files by size, by date, recursively etc.
  • more filename — shows the first part of a file, just as much as will fit on one screen. Just hit the space bar to see more or q to quit. You can use /pattern to search for a pattern.
  • emacs filename — is an editor that lets you create and edit a file. See the emacs page.
  • mv filename1 filename2 — moves a file (i.e. gives it a different name, or moves it into a different directory (see below)
  • cp filename1 filename2 — copies a file
  • rm filename — removes a file. It is wise to use the option rm -i, which will ask you for confirmation before actually deleting anything. You can make this your default by making an alias in your .cshrc file.
  • diff filename1 filename2 — compares files, and shows where they differ
  • wc filename — tells you how many lines, words, and characters there are in a file
  • chmod options filename — lets you change the read, write, and execute permissions on your files. The default is that only you can look at them and change them, but you may sometimes want to change these permissions. For example, chmod o+rfilename will make the file readable for everyone, and chmod o-r filename will make it unreadable for others again. Note that for someone to be able to actually look at the file the directories it is in need to be at least executable. See help protection for more details.
  • File Compression

    • gzip filename — compresses files, so that they take up much less space. Usually text files compress to about half their original size, but it depends very much on the size of the file and the nature of the contents. There are other tools for this purpose, too (e.g. compress), but gzip usually gives the highest compression rate. Gzip produces files with the ending '.gz' appended to the original filename.
    • gunzip filename — uncompresses files compressed by gzip.
    • gzcat filename — lets you look at a gzipped file without actually having to gunzip it (same as gunzip -c). You can even print it directly, using gzcat filename | lpr
  • printing

    • lpr filename — print. Use the -P option to specify the printer name if you want to use a printer other than your default printer. For example, if you want to print double-sided, use 'lpr -Pvalkyr-d', or if you're at CSLI, you may want to use 'lpr -Pcord115-d'. See 'help printers' for more information about printers and their locations.
    • lpq — check out the printer queue, e.g. to get the number needed for removal, or to see how many other files will be printed before yours will come out
    • lprm jobnumber — remove something from the printer queue. You can find the job number by using lpq. Theoretically you also have to specify a printer name, but this isn't necessary as long as you use your default printer in the department.
    • genscript — converts plain text files into postscript for printing, and gives you some options for formatting. Consider making an alias like alias ecop 'genscript -2 -r \!* | lpr -h -Pvalkyr' to print two pages on one piece of paper.
    • dvips filename — print .dvi files (i.e. files produced by LaTeX). You can use dviselect to print only selected pages. See the LaTeX page for more information about how to save paper when printing drafts.

Directories, like folders on a Macintosh, are used to group files together in a hierarchical structure.

  • mkdir dirname — make a new directory
  • cd dirname — change directory. You basically 'go' to another directory, and you will see the files in that directory when you do 'ls'. You always start out in your 'home directory', and you can get back there by typing 'cd' without arguments. 'cd ..' will get you one level up from your current position. You don't have to walk along step by step – you can make big leaps or avoid walking around by specifying pathnames.
  • pwd — tells you where you currently are.
Finding things
  • ff — find files anywhere on the system. This can be extremely useful if you've forgotten in which directory you put a file, but do remember the name. In fact, if you use ff -p you don't even need the full name, just the beginning. This can also be useful for finding other things on the system, e.g. documentation.
  • grep string filename(s) — looks for the string in the files. This can be useful a lot of purposes, e.g. finding the right file among many, figuring out which is the right version of something, and even doing serious corpus work. grep comes in several varieties (grepegrep, and fgrep) and has a lot of very flexible options. Check out the man pages if this sounds good to you.
About other people
  • w — tells you who's logged in, and what they're doing. Especially useful: the 'idle' part. This allows you to see whether they're actually sitting there typing away at their keyboards right at the moment.
  • who — tells you who's logged on, and where they're coming from. Useful if you're looking for someone who's actually physically in the same building as you, or in some other particular location.
  • finger username — gives you lots of information about that user, e.g. when they last read their mail and whether they're logged in. Often people put other practical information, such as phone numbers and addresses, in a file called .plan. This information is also displayed by 'finger'.
  • last -1 username — tells you when the user last logged on and off and from where. Without any options, last will give you a list of everyone's logins.
  • talk username — lets you have a (typed) conversation with another user
  • write username — lets you exchange one-line messages with another user
  • elm — lets you send e-mail messages to people around the world (and, of course, read them). It's not the only mailer you can use, but the one we recommend. See the elm page, and find out about the departmental mailing lists (which you can also find in /user/linguistics/helpfile).
About your (electronic) self
  • whoami — returns your username. Sounds useless, but isn't. You may need to find out who it is who forgot to log out somewhere, and make sure *you* have logged out.
  • finger & .plan files 
    of course you can finger yourself, too. That can be useful e.g. as a quick check whether you got new mail. Try to create a useful .plan file soon. Look at other people's .plan files for ideas. The file needs to be readable for everyone in order to be visible through 'finger'. Do 'chmod a+r .plan' if necessary. You should realize that this information is accessible from anywhere in the world, not just to other people on turing.
  • passwd — lets you change your password, which you should do regularly (at least once a year). See the LRB guide and/or look at help password.
  • ps -u yourusername — lists your processes. Contains lots of information about them, including the process ID, which you need if you have to kill a process. Normally, when you have been kicked out of a dialin session or have otherwise managed to get yourself disconnected abruptly, this list will contain the processes you need to kill. Those may include the shell (tcsh or whatever you're using), and anything you were running, for example emacs or elm. Be careful not to kill your current shell – the one with the number closer to the one of the ps command you're currently running. But if it happens, don't panic. Just try again 🙂 If you're using an X-display you may have to kill some X processes before you can start them again. These will show only when you use ps -efl, because they're root processes.
  • kill PID — kills (ends) the processes with the ID you gave. This works only for your own processes, of course. Get the ID by using ps. If the process doesn't 'die' properly, use the option -9. But attempt without that option first, because it doesn't give the process a chance to finish possibly important business before dying. You may need to kill processes for example if your modem connection was interrupted and you didn't get logged out properly, which sometimes happens.
  • quota -v — show what your disk quota is (i.e. how much space you have to store files), how much you're actually using, and in case you've exceeded your quota (which you'll be given an automatic warning about by the system) how much time you have left to sort them out (by deleting or gzipping some, or moving them to your own computer).
  • du filename — shows the disk usage of the files and directories in filename (without argument the current directory is used). du -s gives only a total.
  • last yourusername — lists your last logins. Can be a useful memory aid for when you were where, how long you've been working for, and keeping track of your phonebill if you're making a non-local phonecall for dialling in.
Connecting to the outside world
  • nn — allows you to read news. It will first let you read the news local to turing, and then the remote news. If you want to read only the local or remote news, you can use nnl or nnr, respectively. To learn more about nn type nn, then \tty{:man}, then \tty{=.*}, then \tty{Z}, then hit the space bar to step through the manual. Or look at the man page. Or check out the hypertext nn FAQ – probably the easiest and most fun way to go.
  • rlogin hostname — lets you connect to a remote host
  • telnet hostname — also lets you connect to a remote host. Use rlogin whenever possible.
  • ftp hostname — lets you download files from a remote host which is set up as an ftp-server. This is a common method for exchanging academic papers and drafts. If you need to make a paper of yours available in this way, you can (temporarily) put a copy in /user/ftp/pub/TMP. For more permanent solutions, ask Emma. The most important commands within ftp are get for getting files from the remote machine, and put for putting them there (mget and mput let you specify more than one file at once). Sounds straightforward, but be sure not to confuse the two, especially when your physical location doesn't correspond to the direction of the ftp connection you're making. ftp just overwrites files with the same filename. If you're transferring anything other than ASCII text, use binary mode.
  • lynx — lets you browse the web from an ordinary terminal. Of course you can see only the text, not the pictures. You can type any URL as an argument to the G command. When you're doing this from any Stanford host you can leave out part of the URL when connecting to Stanford URLs. Type H at any time to learn more about lynx, and Q to exit.
Miscellaneous tools
  • webster word — looks up the word in an electronic version of Webster's dictionary and returns the definition(s)
  • date — shows the current date and time.
  • cal — shows a calendar of the current month. Use e.g., 'cal 10 1995' to get that for October 95, or 'cal 1995' to get the whole year.


Create an alias for a command sequence, see csh(1)
locate commands by keyword lookup
display a string in large letters
arbitrary-precision arithmetic language
Run a suspended job in the background, see csh(1)
display a calendar
send/cancel requests to a printer
concatenate and display
C compiler
change working directory
change the group ownership of a file
change the permissions mode of a file
change local or NIS password information
clear the terminal screen
compress or expand files
copy files
install, edit, remove or list a user's crontab file
shell with a C-like syntax and advanced interactive features
display or set the date
source-level debugger
report free disk space on file systems
display line-by-line differences between pairs of text files
compare directories
Display the directory stack, see csh(1)
convert text file from DOS format to ISO format
display the number of disk blocks used per directory or file
echo arguments to the standard output
search a file for a string or regular expression
eject media device from drive
Execute a command in place of the current shell, see csh(1)
Exit the current shell, see csh(1)
format diskettes
Resume executing a suspended job in the foreground, see csh(1)
search a file for a string or regular expression
determine the type of a file by examining its contents
find files by name, or by other characteristics
display information about users
display the sender and date of newly-arrived mail messages
file transfer program
search a file for a string or regular expression
display a user's group memberships
display first few lines of specified files
Display recently typed commands, see csh(1)
print the numeric identifier of the current host
set or print name of current host system
print the user name and ID, and group name and ID
List jobs suspended or backgrounded from this shell, see csh(1)
send a signal to a process, or terminate a process
indicate last logins by user or terminal
Set or display resource limits, see csh(1)
read one line
a C program verifier
make hard or symbolic links to files
log in to the system
get the name by which you logged in
Terminate a login shell, see csh(1)
send/cancel requests to a printer
display the queue of printer jobs
send a job to the printer
remove jobs from the printer queue
display the printer status information
list the contents of a directory
display the processor type of the current host
display reference manual pages
permit or deny messages on the terminal
make a directory
browse or page through a text file
move or rename files
log in to a new group
run a command at low priority
change local or password information
Pop the directory stack, see csh(1)
display environment variables currently set
display the status of current processes
Push a directory onto the directory stack, see csh(1)
display the pathname of the current working directory
display a user's disk quota and usage
Rescan the execution path, see csh(1)
establish or restore terminal characteristics
remote login
remove (unlink) files or directories
remove (unlink) files or directories
remote shell
show host status of local machines (RPC version)
show host status of local machines
who's logged in on local machines (RPC version)
write to all users over a network
who's logged in on local machines
make typescript of a terminal session
Set or display environment variables, see csh(1)
Set or display shell variables, see csh(1)
standard UNIX system shell and command-level language
suspend execution for a specified interval
sort and collate lines
Read commands from a file, see csh(1)
report spelling errors
report spelling errors
find printable strings in an object file or binary
remove symbols and relocation bits from an object file
set or alter the options for a terminal
super-user, temporarily switch to a new user ID
Suspend the shell, see csh(1)
update the super block; force changed blocks to the disk
display the last part of a file
talk to another user
create tape archives, and add or extract files
user interface to a remote system using the TELNET protocol
time a command
update the access and modification times of a file
trace system calls and signals
establish or restore terminal characteristics
display the name of the terminal
Set or display the file permissions mask, see csh(1)
Discard an alias, see csh(1)
compress or expand files, display expanded contents
convert text file from ISO format to DOS format
Remove a limit on a resource, see csh(1)
Discard a shell variable, see csh(1)
Discard an envrionment variable, see csh(1)
show how long the system has been up
display a compact list of users logged in
encode a binary file, or decode its ASCII representation
encode a binary file, or decode its ASCII representation
reply to mail automatically
who is logged in, and what are they doing
write to all users logged in
display a count of lines, words and characters
display a one-line summary about a keyword
locate the binary, source, and manual page for a command
locate a command; display its pathname or alias
who is logged in on the system
display the effective current username
Internet user name directory service
write a message to another user
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Salary packaging for social workers in Australia


tax-free salary pkging benefits up to $16,050 p/a

What are fringe benefits? 

The most common fringe benefits are expense payment reimbursements.  Expense payment 
reimbursements include personal expenses paid by an employer on behalf of a staff 
member.  For example, payment of home mortgage repayments, private health insurance, 
children’s school fees and so on.  Payment of personal expenses can be made either directly 
by the employer to the supplier, or the employer can reimburse the cost of the expense to the 
staff member. 
Why package personal expenses? 
Depending on the expense, substantial savings can be made by staff from having 
Centrecare pay personal expenses on their behalf. 
By agreeing to take the lower cash salary of $25,000 and have Centrecare make their 
mortgage payments as part of their salary package, this staff member will save $3,150 (after 
tax) per year.  Looked at another way, the gain equates to a 13.1% pay rise and has 
increased the market value of the staff member’s remuneration from $35,000 to $39,600
OzChild has very generous salary packaging provisions for staff, permitting staff to salary package 
$16,050 per annum.  This equates to approximately $6,000 in addition to the gross SACS Award 
rate.  Staff may also elect to package items such meal entertainment and venue hire; this is in 
addition to the salary packaging. 

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