[bash] zcat does not work on MACOS (.Z bug)
sudo mv /usr/bin/zcat /usr/bin/broken-zcat sudo ln -s /usr/bin/gzcat /usr/bin/zcat
[bash] awk insert blank line every n lines
awk '{ if ((NR % 5) == 0) printf("\n"); print; }'
for n == 5, of course. Substitute whatever your idea of n is.
[bash] convert windows source file to unix
dos2unix *.py
[bash] remove first column from a file
cut -f2- filename
[bash] replace delete with backspace in screen
You can define an alias in your ~/.bashrc file like
alias screen='TERM=screen screen'
[java] generate classpath
[OLD use maven ;)] all the jars in a directory:
JAR=$(for i in $(ls); do echo $(pwd)/$i; done | tr "\n" ":").
recorsive:
JAR=$(find . -type f | sed "s#^.#$(pwd)#" | egrep ".*jar$" | tr "\n" ":" ).
[maven] create a jar with all the dependecies in maven
add this snippet to the code
<build> <plugins> <plugin> <artifactId>maven-assembly-plugin</artifactId> <configuration> <archive> <manifest> <mainClass>fully.qualified.MainClass</mainClass> </manifest> </archive> <descriptorRefs> <descriptorRef>jar-with-dependencies</descriptorRef> </descriptorRefs> </configuration> </plugin> </plugins> </build>
compile using
mvn assembly:assembly
produce a jar (..with-dependences) with all the dependecies
[bash] sort using tab as separator
sort -t$'\t' -k 2 file
[java] change java heap size
java -Xmx<size> set maximum Java heap size e.g. java -Xmx4196m Pippo
[bash] resolve redirected url
URL=...
REDIRECT_URL=$(curl -w %{redirect_url} URL)
my bashrc
[bash] get a txt file edited from pirate pad
curl http://piratepad.net/ep/pad/export/$id/latest?format=txt
[java] does not find JAVA_HOME
export JAVA_HOME=a/usr/lib/jvm/java-6-sun-1.6.0.22/a
ornellaia export JAVA_HOME=/usr/lib/jvm/java-6-sun-1.6.0.24/
[bash] dump a website
wget -r -H -l1 -k -P $targetdir --exclude-domains ${comma-seperated domain name} --user=xxx --password=xxx $url
[bash] get a webpage with autentication
url= "" outpage = "" user="" pass="" curl -u $user:$pass $url > $outpage
[bash] number of results for a query on google
query=pippo+pluto results=$(curl -A "Firefox/3.0" http://www.google.com/search?q=$query | egrep -o "About [1234567890,]+ results" | tr -d ' ,Aboutresults')
[linux] 10 nice hints
[bash] how to get the sum of all the lines in the file
awk '{a+=$0}END{print a}' abc
[python] remove the garbage collector in python
when you are working with big data structure in python the garbage collector can slow down the exection, sometime is better to disable it
import gc gc.disable()
[bash] how to query solr from the shell
[bash] sum rows with the some field
dictionary in awk:
$ cat nayan.out
saman 1
gihan 2
saman 4
ravi 1
ravi 2
$ awk '{arr[$1]+=$2} END {for (i in arr) {print i,arr[i]}}' nayan.out > nayan.out.tmp
$ cat nayan.out.tmp
ravi 3
saman 5
gihan 2
[maven] resources in a jar
[bash] get all pdf in a page
wget -m --accept=pdf -nd $url
[bash] iterate over the lines of a jar
while read line do echo $line done < file_to_read
[bash] remove blank lines in a file
grep -v '^[[:space:]]*$' file
[bash] change tmp folder where sort put temporary files
sort -T dir ...
[bash] print number of a specific char for each line of a file
awk -F'#' '{ print NF-1}'
prints how many chars '#' per line
[bash] replace a substring
i=pippo.txt
echo ${i/txt/tex}
#stamp pippo.tex
[bash] sort on more than one field
sort -k 1,1 -k 3,3nr file.tsv > tmp
sort on the first field and if two elements are equals on the first, on the third field in reverse integer order
[bash] remove all files of size 0
find . -type f -size 0k -exec rm {} \; | awk '{ print $8 }'
[bash] remove all chars in a particular position from a file
cut -c44- file
removes the first 44 characters from all the lines of file
[bash] view what is appended on file
tail -f file -n
[bash] get words distribution from a file
cat file | tr '[A-Z]' '[a-z]' | tr -sc '[a-z]' '\n' | grep -v '^[^a-z]*$' | grep -v '^[\]' | sort | grep -vxf topwords-ita.txt | uniq -c | sort -nrk1
[bash] tr complement
tr -sc '[a-zA-Z]' '\n' < file
replace all chars that are not alphabetic in new lines
[bash] remove first or last lines
sed '1d' filename
the first line
sed '$d' filename
the last line
[bash] check bash parameters
# Check for proper number of command line args.
EXPECTED_ARGS=1
E_BADARGS=65
if [ $# -ne $EXPECTED_ARGS ]
then
echo "Usage: `basename $0` {arg}"
exit $E_BADARGS
fi
[bash] Generate all the couples of terms
tr -sc '[a-zA-Z0-9\n]' '\t' < inputFile | awk '{for (i = 1; i < NF; i++) print $i"\t"$(i+1); }'
[bash] Find a process listening on a particular port
sudo netstat -lpn |grep :8080
[bash] Check for proper number of command line args
EXPECTED_ARGS=1
E_BADARGS=65
if [ $# -ne $EXPECTED_ARGS ]
then
echo "Usage: `basename $0` {arg}"
exit $E_BADARGS
fi
[bash] Sort in numeric order with scientific notation allowed
sort -g
[bash] create ssh pub key
<ssh-keygen -t rsa -C "your_email@example.com" # Creates a new ssh key, using the provided email as a label # Generating public/private rsa key pair. # Enter file in which to save the key (/Users/you/.ssh/id_rsa): [Press enter]
Now you need to enter a passphrase.
Enter passphrase (empty for no passphrase): [Type a passphrase] # Enter same passphrase again: [Type passphrase again]
copy iid_rsa.pub in .ssh/authorized_key
[bash] gzip a folder
tar -czf folder_name.tar.gz folder_name/
