A list of some of my favorite unix commands

When I say "favorite", I mean that I use them too rarely to memorize them but often enough that I'd like to have them saved somewhere.
If this page is interesting, you may also want to see my Mac commands page
sudo /etc/init.d/vpnclient_init start initialize the vpnclient service
sudo vpnclient connect cuboulder connect to CU's VPN service from off-campus
sudo vpnclient connect oncampus connect to CU's VPN service from on-campus
ls --color=never | grep "old" | xargs -n1 rm remove a list of files (in this case, list containing the string old
cat 2007-11-12T23\:53\:40.log | grep TEMP= | sed -e 's/.*TEMP=//' -e 's/,/ /g' -e "s/'//" > log_to_plot.txt NICFPS log file parsing to send to gnuplot
echo "plot [][] 'plotfile.tsv' index 0 using 1:($2-$3)" | gnuplot -persist Plot the contents of a file using gnuplot

Image resize / thumbnail creation using imagemagick's convert command

ls *.gif | sed 's/$.*$.gif/\/sw\/bin\/convert \1.gif -resize 100x100 thumbs\/\1_tn.gif/' | bash using imagemagick's convert to create thumbnails
ls *.png | sed 's:$.*$.png:/sw/bin/convert \1.png -resize 100x100 thumbs/\1_tn.png:' | bash using imagemagick's convert to create thumbnails (full path)
ls *.png | sed 's:$.*$.png:/sw/bin/convert \1.png -resize 800x800 ../\1.png:' | bash using imagemagick's convert to create smaller images
ls *.jpg | sed 's:$.*$.jpg:/sw/bin/convert \1.jpg -resize 100x100 thumbs/\1_tn.jpg:' | bash jpg thumbnails
pstoimg -type png -crop a -density 600 *.ps using latex2html
cat trackdb.121207.txt | grep google | grep search | sed -e "s/.*[?\&\_]q=$.*\?$\&.*/\1/" | less Search my tracker for hits from Google so I can see what search terms have been used to find this site

IRAF:

imhead *.fits lo+ | grep -E "Pixel\ file\|EXPTIME" find exposure times and file name for all fits files using IRAF's imhead
echo "from pyraf import iraf; s=iraf.imhead('*.fits',long='yes',Stdout=1); iraf.grep('-E EXPTIME\|Pixel\ file',Stdin=s)" | python same using pyraf from command line

Python:

numarray.concatenate = numpy.hstack (numpy.concatenate is not equivalent to numarray.concatenate, it does not accept scalars)
glob.glob(filename) filename retrieval with wildcards
"Grep" type search with Python: Python lacks a simple "grep" command to scan a list; I've written one
for i in dir(): print "%s: %s" % (i,eval(i)) a useful quick look at all the variables available (particularly useful when using pdb, the interactive debugger

VIM:

There are some tasks too complicated for vim's internal substitution commands
%!perl -pe 's/(.*AREA HEIGHT.*WIDTH=")([0-9\.]*)(.*)/$1.($2+120).$3/e' is a complicated statement: it replaces a number that occurs after WIDTH= with that number + 120. The line number to operate on must be specified, even if it is global (% or g//). Dots connect the output statements within the perl replacement side. /e evaluates the replacement side rather than just printing it. The parentheses are required.
%!awk '{print "point("$2":"$3":"$4","$5":"$6":"$7") \# point=arrow text={"$1"}"}' Reformat catalog as DS9 region file
%!awk 'BEGIN {FS="|"} {print $5" "$3}' %!awk '{print "point("$1":"$2":"$3","$4":"$5":"$6") \# text={"$7" "$8" "$9" "$10" "$11" "$12"}"}' SIMBAD catalog to ds9 regions file (requires significant filtering because SIMBAD is inconsistent between lines)
s/(.\{-})// is the non-greedy version of s/(.*)//

'<,'>s/$.*$\.$.*$$.png$/<h3>\2</h3>\r<img src="images\/orion\/thumbs\/\1.\2_tn.png" \ronclick="toggle('\1','images\/orion\/thumbs\/\1_tn.png','images\/orion\/\1.png')" \rname="\1">

%s/<a href="images\/$.*$$...g$"><img src="$.*$"><\/a>/<img src="\3" onclick="toggle('\1','\3','images\/\1\2')" name="\1">/

%s/$.*$$.jpg$/<img src="images\/jcmt\/thumbs\/\1_tn.jpg" onclick="toggle('\1','images\/jcmt\/thumbs\/\1_tn.jpg','images\/jcmt\/\1.jpg')" name="\1">/

'<,'>s/$.*$$.jpg$/<img src="images\/jcmt\/thumbs\/\1_tn.jpg" \r\tonclick="toggle('\1','\1_tn.jpg','\1.jpg')" \r\tname="\1">/
%!awk '{print "union select s.*,n"NR".universalid as n"NR"universalid from sagecatalog as s, fGetNearbyObjEqUTC("$1","$2".02 as n"NR" where n"NR".universalid=s.universalid and s.epoch="}'
5,30!awk 'BEGIN {OFS=""} {a = substr($0,12,2); print substr($0,0,11) , ":" , sprintf("\%2.2d",a*60.) , substr($0,14,100)}' arithmetic operations using AWK instead of SED (useful when a catalog outputs decimal arcminute units when you want arcseconds)
ESSENTIAL: if backspace in insert mode fails, you must :set bs=2. VIM becomes VI - and, imo, generally unusable - without this.

Apache Server:

/etc/init.d/apache2 start Initiate daemon
/etc/apache2/apache2.conf Configuration file (can use ln -s to link a new home directory to your default /var/www)
The .htaccess file allows you to modify the way files are processed in a given directory.
Apache server in Ubuntu

More to come, but in the meantime these pages are recommended:
Pat Hartigan's Computer Page

Anyone who has attempted to install a unix system should be familiar with this

Perl

perl -ne 'if (/RA/ && /DEC/) {$_ =~ m/RA *= .([0-9:\.]*)/; print $1,"\t"; $_ =~ m/DEC *= .([0-9:\.-]*)/; print $1,"\n";'} a hideously ugly and relatively slow way to extract RA and DEC from fits files. Does NOT print the file name

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