Bii a ṣe le Lo awọn aṣẹ o nran ati tac pẹlu Awọn apẹẹrẹ ni Lainos
Nkan yii jẹ apakan ti Lainos Awọn ẹtan wa ati jara Awọn imọran, ninu nkan yii a yoo bo diẹ ninu lilo ipilẹ ti aṣẹ ologbo (aṣẹ ti a nlo nigbagbogbo ni Linux) ati tac (yiyipada aṣẹ aṣẹ ologbo - tẹjade awọn faili ni aṣẹ yiyipada) pẹlu diẹ ninu iṣe awọn apẹẹrẹ.
Ipilẹ Lilo ti Cat Cat ni Linux
Aṣẹ Cat, adape fun Concatenate, jẹ ọkan ninu awọn ofin ti a lo julọ ni awọn ọna ṣiṣe * nix. Lilo ipilẹ ti aṣẹ julọ ni lati ka awọn faili ati ṣafihan wọn si stdout, itumo lati ṣafihan akoonu ti awọn faili lori ebute rẹ.
# cat file.txt
Lilo miiran ti aṣẹ ologbo ni lati ka tabi ṣapọpọ awọn faili lọpọlọpọ ati firanṣẹ iṣiṣẹ si atẹle bi a ti ṣe apejuwe ninu awọn apẹẹrẹ isalẹ.
# cat file1.txt file2.txt file3.txt
A tun le lo aṣẹ lati ṣe apejọ (darapọ mọ) awọn faili lọpọlọpọ sinu faili kan ṣoṣo nipa lilo \">” Oniṣẹ redirection Linux.
# cat file1.txt file2.txt file3.txt > file-all.txt
Nipa lilo redirector append o le ṣafikun akoonu ti faili tuntun si isalẹ ti file-all.txt pẹlu sintasi atẹle.
# cat file4.txt >> file-all.txt
A le lo aṣẹ ologbo lati daakọ akoonu faili si faili tuntun kan. Faili tuntun le ṣe lorukọ lainidii. Fun apẹẹrẹ, daakọ faili naa lati ipo lọwọlọwọ si itọsọna /tmp/.
# cat file1.txt > /tmp/file1.txt
Daakọ faili naa lati ipo lọwọlọwọ si /tmp/ itọsọna ki o yi orukọ rẹ pada.
# cat file1.txt > /tmp/newfile.cfg
Lilo ti o kere ju ti aṣẹ ologbo ni lati ṣẹda faili tuntun pẹlu sintasi isalẹ. Nigbati o ba pari ṣiṣatunkọ faili lu CTRL + D lati fipamọ ati jade kuro ni faili tuntun naa.
# cat > new_file.txt
Lati le ka nọmba gbogbo awọn ila ilajade faili kan, pẹlu awọn laini ofo, lo iyipada -n .
# cat -n file-all.txt
Lati ṣe afihan nọmba nikan ti laini ti ko ṣofo kọọkan lo iyipada -b .
# cat -b file-all.txt
Fẹ lati ni imọ siwaju sii nipa aṣẹ nran Linux? lẹhinna ka nkan wa nipa 13 Awọn iwulo ‘ologbo’ Apeere Aṣẹ ni Linux.
Kọ ẹkọ Bii o ṣe le Lo Tac Command ni Linux
Ni apa keji, aṣẹ ti o mọ ti o kere si ti a ko lo ni awọn ọna ẹrọ nix ni tac pipaṣẹ. Tac jẹ iṣe ikede yiyipada ti cat pipaṣẹ (tun ṣe akọtọ sẹhin) eyiti o tẹ ila kọọkan ti faili kan ti o bẹrẹ lati laini isalẹ ati ipari lori laini oke si iṣelọpọ boṣewa ẹrọ rẹ.
# tac file-all.txt
Ọkan ninu aṣayan ti o ṣe pataki julọ ti aṣẹ ni ipoduduro nipasẹ iyipada -s , eyiti o ya awọn akoonu ti faili da lori okun tabi ọrọ koko kan lati faili naa.
# tac file-all.txt --separator "two"
Nigbamii, lilo pataki julọ ti aṣẹ tac ni, pe o le pese iranlọwọ nla lati le yokokoro awọn faili log, yiyipada aṣẹ-akọọlẹ ti awọn akoonu log.
$ tac /var/log/auth.log Or to display the last lines $ tail /var/log/auth.log | tac
[email ~ $ tac /var/log/auth.log pr 6 16:09:01 tecmint CRON[17714]: pam_unix(cron:session): session closed for user root Apr 6 16:09:01 tecmint CRON[17714]: pam_unix(cron:session): session opened for user root by (uid=0) Apr 6 16:05:01 tecmint CRON[17582]: pam_unix(cron:session): session closed for user root Apr 6 16:05:01 tecmint CRON[17583]: pam_unix(cron:session): session closed for user root Apr 6 16:05:01 tecmint CRON[17583]: pam_unix(cron:session): session opened for user root by (uid=0) Apr 6 16:05:01 tecmint CRON[17582]: pam_unix(cron:session): session opened for user root by (uid=0) Apr 6 16:00:01 tecmint CRON[17434]: pam_unix(cron:session): session closed for user root ....
[email ~ $ tail /var/log/auth.log | tac Apr 6 16:09:01 tecmint CRON[17714]: pam_unix(cron:session): session closed for user root Apr 6 16:09:01 tecmint CRON[17714]: pam_unix(cron:session): session opened for user root by (uid=0) Apr 6 16:05:01 tecmint CRON[17582]: pam_unix(cron:session): session closed for user root Apr 6 16:05:01 tecmint CRON[17583]: pam_unix(cron:session): session closed for user root Apr 6 16:05:01 tecmint CRON[17583]: pam_unix(cron:session): session opened for user root by (uid=0) Apr 6 16:05:01 tecmint CRON[17582]: pam_unix(cron:session): session opened for user root by (uid=0) Apr 6 16:00:01 tecmint CRON[17434]: pam_unix(cron:session): session closed for user root Apr 6 16:00:01 tecmint CRON[17434]: pam_unix(cron:session): session opened for user root by (uid=0) Apr 6 15:55:02 tecmint CRON[17194]: pam_unix(cron:session): session closed for user root Apr 6 15:55:01 tecmint CRON[17195]: pam_unix(cron:session): session closed for user root ...
Bakanna bi cat pipaṣẹ, tac ṣe iṣẹ ti o dara julọ ni ifọwọyi awọn faili ọrọ, ṣugbọn o yẹ ki a yee ni iru awọn faili miiran, paapaa awọn faili alakomeji tabi lori awọn faili nibiti laini akọkọ tọka eto ti yoo ṣiṣẹ.