UNIX : grep command examples

GREP (Global Regular Expression and Print) is a utility used to search for lines containing the string in a file.

Syntax of GREP is : grep [option] [pattern] [ files]

1. Search for lines in a file that contains a word .

> grep "word" <filename>

2. How to search for more than one matching string in a file?

>egrep "a|b|c" <filename>

Comments

UNIX : How to get record count from zipped file

Sometimes we may need to get records count from file . For that we can use wc -l , command with file name. In some situation the file will be in compressed format . wc -l will not directly work with zipped files . In this case we can do zcat the file and pipe the word count command with it. Example : Let say we have a file cricketData.dat.gz To get word count from the file use : zcat cricketData.dat.gz | wc -l This will give the record count.

UNIX : How to ignore lines with certain names

Sometimes we need to ignore multiple lines with certain words and get the list out of the file. usually it will be a log file to read . The below grep command can be used to ignore multiple words present in a text file. Lets say the file contain $ cat list.txt apple orange apple banana papaya Now we need to ignore line with orange , banana and papaya . So we can use the below grep command. $ cat list.txt | grep -Ev "orange|banana|papaya" apple apple It will ignore lines with the words in -v part of grep.

Scala

Scala is a object oriented functional type programing language. All variables declared in scala is considered as objects.

Tech Info Talks

Search This Blog