Grep text search tool

List of articles

1.1 Compression and decompression commands
2.1 head、tail see file
3 grep Text search tools

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One 、grep

grep The command is used to find the strings in the file that match the conditions .
grep Command is used to find a file whose content contains the specified template style , If the content of a file is found to conform to the specified template style , Preset grep The command displays the column containing the template style .

Use format ：

grep [-option] ' Conditions ' [ file / Catalog ]

Common parameters	significance
-v	Display does not contain matching text of all lines .
-i	Ignore character case differences .
-c	Calculated in line with the number of columns styles .

For example, view fasta How many sequences are there in the file ：

grep -c '>' all_viruses_nucleotide_sequences_20171115.fasta
270

see fasta In file WHW Opening file ：

grep '>WHW' all_viruses_nucleotide_sequences_20171115.fasta
>WHWGC149849_Chinese_broad-headed_pond_turtle_astro-like_virus_9296bp
>WHWGC150683_Chinese_broad-headed_pond_turtle_arterivirus_14939bp
>WHWGC151314_Chinese_broad-headed_pond_turtle_picornavirus_1_9218bp
>WHWGGF74766_Tortoise_Rafivirus_A_7315bp
>WHWGGF75534_Chinese_broad-headed_pond_turtle_picornavirus_2_7999bp
>WHWGGF64311_Chinese_broad-headed_pond_turtle_hepacivirus_8764bp

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