One of the commands used when administering a UNIX or Linux command line is doubtless `grep`.
For those who do not know, I will simply say that it is an efficient and highly flexible script can detect regular expressions in a file or a text output.
The command name is in fact stands for "global regular expression-print".
Everything else can be found with the usual `man grep`.
For those who usually use grep for the administrative tasks of every day, I collect here a number of examples to use a little 'more advanced and - perhaps - unusual.
May be useful to you as they were to me on numerous occasions.
Find occurrences of the sequence here, here in court AND file.txt:
grep "qui.*quo.*qua" ./file.txt
Find occurrences of OR here OR here in court file.txt:
grep -P 'qui|quo|qua' ./file.txt
Verify that a properly formatted email address is:
echo "info@test.eu" | grep -Ei '\b[a-z0-9]{1,}@*\.(it|eu|com|net|org|tv)\b'
Find the word here in a case in-sensitive in the. / File.txt:
grep -iw "is" demo_file
Find email addresses formatted as test.txt <qwerty.qwerty@qwerty.com> enclosure and removes characters (<and>):
grep -o '<.*@.*\.*>' ./test.txt | tr -d '<>'
Find multiple occurrences of OR here OR here in court a string of text:
echo -e "1) qui quo qua\n2) quo qui qua\n3)qui quo qui\n4) qua quo qui\n" | grep -E '(qui|quo|qua).*\1'
Check if the string is passed through pipes or not an IP address (try passing a bad IP address format):
echo "192.168.123.123" | grep -E '\b((25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.){3}(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\b'
Show all rows dell'httpd. Conf omitting the instructions commented:
grep -v -E '^\#|^$' /etc/apache2/httpd.conf
Assuming that test.sh script contains the following instructions:
#!/bin/bash
contatore=1
until [ $contatore -gt 10 ]; do
echo contatore $contatore
let contatore+=1
done
... Identifies the following command line 4 and the 3 following lines:
./test.sh | grep -A 3 -i "contatore 4"
... The following command instead identifies all lines except those containing 4 and 6:
./test.sh | grep -v -e "4" -e "6"
The official website of the project is located at grep http://gnu.org/software/grep/ .
The Linux Foundation has announced a new initiative to inspire the worst - so to speak - geeks around the world: a wonderful credit card number plate Linux.
This is not a gadget, but a real Visa Platinum whose use will help to finance the projects of the Federal Act.
Activation Minimum Cost: only $ 50, although for the moment the card is only available in the States - but I'm sure that soon we will circulate our own in July.
Similar initiatives have been tried in the past by LinuxFund and BSDFund .
The news of the day is fresh and comes from ZDNetUK , but also find the official announcement on the website of the Federal Act to address this (was yesterday). 
