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About sed : How-to-use-awk-to-print-lines-where-a-field-matches-a-specific-string

Question Detail

I have:

1 LINUX param1 value1 
2 LINUXparam2 value2
3 SOLARIS param3 value3
4 SOLARIS param4 value4

I need awk to print all lines in which $2 is LINUX.

Question Answer

In awk:

awk '$2 == "LINUX" { print $0 }' test.txt

See awk by Example for a good intro to awk.

In sed:

sed -n -e '/^[0-9][0-9]* LINUX/p' test.txt

See sed by Example for a good intro to sed.

This is a case in which you can use the beautiful idiomatic awk:

awk '$2=="LINUX"' file

That is:

  • The default action of awk when in a True condition is to print the current line.
  • Since $2 == "LINUX" is true whenever the 2nd field is LINUX, this will print those lines in which this happens.

In case you want to print all those lines matching LINUX no matter if it is upper or lowercase, use toupper() to capitalize them all:

awk 'toupper($2)=="LINUX"' file

Or IGNORECASE with either of these syntaxs:

awk 'BEGIN {IGNORECASE=1} $2=="LINUX"' file
awk -v IGNORECASE=1 '$2=="LINUX"' file

My answer is very late, but no one has mentioned:

awk '$2~/LINUX/' file

Try these out:

egrep -i '^\w+ LINUX ' myfile

awk '{IGNORECASE=1}{if ($2 == "LINUX") print}' myfile

sed -ne '/^[0-9]* [Ll][Ii][Nn][Uu][Xx] /p' myfile

edit: modified for case insensitivity

I think it might be a good idea to include “exact” and “partial matching” cases using awk ))

So, for exact matching:

OTHER_SHELL_COMMAND | awk '$2 == "LINUX" { print $0 }'

And for partial matching:

OTHER_SHELL_COMMAND | awk '$2 ~ /LINUX/ { print $0 }'

In GNU sed case-insensitive matches can be made using the I modifier:

sed -n '/^[^[:space:]][[:space:]]\+linux[[:space:]]\+/Ip'

Will robustly match “linux”, “Linux”, “LINUX”, “LiNuX” and others as the second field (after the first field which may be any non-whitespace character) and surrounded by any amount (at least one) of any whitespace (primarily space and tab, although you can use [:blank:] to limit it to strictly those).

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