Pipeline | and redirection ＞

List of articles

1.1 Compression and decompression commands
2.1 head、tail see file
3 grep Text search tools
4 The Conduit | And redirect >

---

---

One 、 The Conduit |

The pipeline can only handle the correct output information sent through the previous instruction , That is to say standard output Information about , about standard error Information has no direct processing power .

And then standard output Pass as standard input to the next command .

Use format ：

[ command ] | [ command ]

for example ：

head -n 10 all_viruses_nucleotide_sequences_20171115.fasta | grep '>'
>BHFishC185032_Beihai_conger_calicivirus_6981bp
>BHFishC186477_Beihai_fish_calicivirus_6847bp
>BHFishC187917_Beihai_yellowfin_seabream_calicivirus_6816bp
>BHFishC181798_Beihai_rabbitfish_calicivirus_1_4604bp
>BHFishC188521_Beihai_rabbitfish_calicivirus_2_5721bp

Two 、 Redirect >

Use > You can redirect standard output information that should appear on the screen to a file .

Use format ：

[ command ] > [ command ]

for example ：

head -n 10 all_viruses_nucleotide_sequences_20171115.fasta | grep '>' > BHF.txt
>BHFishC185032_Beihai_conger_calicivirus_6981bp
>BHFishC186477_Beihai_fish_calicivirus_6847bp
>BHFishC187917_Beihai_yellowfin_seabream_calicivirus_6816bp
>BHFishC181798_Beihai_rabbitfish_calicivirus_1_4604bp
>BHFishC188521_Beihai_rabbitfish_calicivirus_2_5721bp
tail -n 10 all_viruses_nucleotide_sequences_20171115.fasta | grep '>' > WHW.txt
>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
>XMTSYG10372_Xiamen_fanray_pesti-like_virus_11039bp
cat WHW.txt BHF.txt > combine.txt
cat combine.txt
>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
>XMTSYG10372_Xiamen_fanray_pesti-like_virus_11039bp
>BHFishC185032_Beihai_conger_calicivirus_6981bp
>BHFishC186477_Beihai_fish_calicivirus_6847bp
>BHFishC187917_Beihai_yellowfin_seabream_calicivirus_6816bp
>BHFishC181798_Beihai_rabbitfish_calicivirus_1_4604bp
>BHFishC188521_Beihai_rabbitfish_calicivirus_2_5721bp