使用 bash 删除字符串中特定出现后的所有文本

Delete all text after a specific occurrence in a string using bash

我有一个序列:

MALYYDHQIEAPDAAGSPSFISWHPVHPFLAVAYISTTSTGSVDIYLEQGECVPDTHVERPFRVASLCWHPTRLVLAVGWETGEVTVFNKQDKEQHTMPLTHTADITVLRWSPSGNCLLSGDRLGVLLLWRLDQRGRVQGTPLLKHEYGKHLTHCIFRLPPPGEDLVQLAKAAVSGDEKALDMFNWKKSSSGSLLKMGSHEGLLFFVSLMDGTVHYVDEKGKTTQVVSADSTIQMLFYMEKREALVVVTENLRLSLYTVPPEGKAEEVMKVKLSGKTGRRADIALIEGSLLVMAVGEAALRFWDIERGENYILSPDEKFGFEKGENMNCVCYCKVKGLLAAGTDRGRVAMWRKVPDFLGSPGAEGKDRWALQTPTELQGNITQIQWGSRKNLLAVNSVISVAILSERAMSSHFHQQVAAMQVSPSLLNVCFLSTGVAHSLRTDMHISGVFATKDAVAVWNGRQVAIFELSGAAIRSAGTFLCETPVLAMHEENVYTVESNRVQVRTWQGTVKQLLLFSETEGNPCFLDICGNFLVVGTDLAHFKSFDLSRREAKAHCSCRSLAELVPGVGGIASLRCSSSGSTISILPSKADNSPDSKICFYDVEMDTVTVFDFKTGQIDRRETLSFNEQETNKSHLFVDEGLKNYVPVNHFWDQSEPRLFVCEAVQETPRSQPQSANGQPQDGRAGPAADVLILSFFISEEHGFLLHESFPRPATSHSLLGMEVPYYYFTRKPEEADREDEVEPGCHHIPQMVSRRPLRDFVGLEDCDKATRDAMLHFSFFVTIGDMDEAFKSIKLIKSEAVWENMARMCVKTQRLDVAKVCLGNMGHARGARALREAEQEPELEARVAVLATQLGMLEDAEQLYRKCKRHDLLNKFYQAAGRWQEALQVAEHHDRVHLRSTYHRYAGHLEASADCSRALSYYEKSDTHRFEVPRMLSEDLPSLELYVNKMKDKTLWRWWAQYLESQGEMDAALHYYELARDHFSLVRIHCFQGNVQKAAQIANETGNLAASYHLARQYESQEEVGQAVHFYTRAQAFKNAIRLCKENGLDDQLMNLALLSSPEDMIEAARYYEEKGVQMDRAVMLYHKAGHFSKALELAFATQQFVALQLIAEDLDETSDPALLARCSDFFIEHSQYERAVELLLAARKYQEALQLCLGQNMSITEEMAEKMTVAKDSSDLPEESRRELLEQIADCCMRQGSYHLATKKYTQAGNKLKAMRALLKSGDTEKITFFASVSRQKEIYIMAANYLQSLDWRKEPEIMKNIIGFYTKGRALDLLAGFYDACAQVEIDEYQNYDKAHGALTEAYKCLAKAKAKSPLDQETRLAQLQSRMALVKRFIQARRTYTEDPKESIKQCELLLEEPDLDSTIRIGDVYGFLVEHYVRKEEYQTAYRFLEEMRRRLPLANMSYYVSPQAVDAVHRGLGLPLPRTVPEQVRHNSMEDARELDEEVVEEADDDP

我想将索引位置 383 (Q) 替换为后面没有任何内容,因此所需的结果将是:

MALYYDHQIEAPDAAGSPSFISWHPVHPFLAVAYISTTSTGSVDIYLEQGECVPDTHVERPFRVASLCWHPTRLVLAVGWETGEVTVFNKQDKEQHTMPLTHTADITVLRWSPSGNCLLSGDRLGVLLLWRLDQRGRVQGTPLLKHEYGKHLTHCIFRLPPPGEDLVQLAKAAVSGDEKALDMFNWKKSSSGSLLKMGSHEGLLFFVSLMDGTVHYVDEKGKTTQVVSADSTIQMLFYMEKREALVVVTENLRLSLYTVPPEGKAEEVMKVKLSGKTGRRADIALIEGSLLVMAVGEAALRFWDIERGENYILSPDEKFGFEKGENMNCVCYCKVKGLLAAGTDRGRVAMWRKVPDFLGSPGAEGKDRWALQTPTELQGNITQ

我试过:

sed 's/"Q"//383' text.file
sed 's/Q//383' text.file

但这没有任何作用。

从长远来看,我需要处理其他一些职位,因此非常感谢一种灵活的方法。

祝一切顺利

你可以用 cut:

cut -c 1-383 < text.file

如果您将字符串存储在 bash 变量中,您可以使用 bash 参数扩展:

mystring=$(cat text.file)
echo "${mystring:0:383}"

这可能适合您 (GNU sed):

sed -zEi 's/(.{383}).*//' file

将前 383 个字符存储为后向引用并删除其余字符。

N.B。 -z 选项将整个文件拖入内存。

就是扔进池子里,head可以用来截断n行后,也可以截断c字节后:

$ head -c 383 text.file

GNU awk:

gawk '{print gensub(/(.{383}).*/,"\1","1")}' file

另一个选项:dd

dd if=txt.file bs=383 count=1 status=none

使用 bashprintf:

 printf '%.383s\n' $(<text.file)