Halaman manual adalah salah satu sumber daya yang paling berguna untuk memahami utilitas baris perintah. Namun, halaman manual berisi banyak detail tentang perintah. Mungkin ada saat-saat ketika Anda ingin segera mengetahui - mungkin dalam garis kecil atau lebih - apa yang dilakukan alat baris perintah. Nah, Anda akan senang mengetahui bahwa ada perintah yang dibuat khusus untuk tujuan ini.
Dalam tutorial ini, kita akan membahas dasar-dasar whatis perintah menggunakan beberapa contoh yang mudah dimengerti. Namun sebelum kita melakukannya, perlu disebutkan bahwa semua contoh di sini telah diuji pada mesin Ubuntu 18.04 LTS dan Debian 10.
Perintah whatis Linux
Perintah whatis di Linux memungkinkan Anda menampilkan deskripsi halaman manual satu baris. Berikut sintaksnya:
whatis [-dlv?V] [-r|-w] [-s list] [-m system[,...]] [-M path] [-L
locale] [-C file] name ...
Dan inilah cara halaman manual alat menjelaskannya:
Each manual page has a short description available within it. whatis
searches the manual page names and displays the manual page descrip?
tions of any name matched.
name may contain wildcards (-w) or be a regular expression (-r). Using
these options, it may be necessary to quote the name or escape (\) the
special characters to stop the shell from interpreting them.
Berikut ini adalah beberapa contoh gaya Tanya Jawab yang akan memberi Anda gambaran yang lebih baik tentang cara kerja perintah whatis.
Q1. Bagaimana cara menggunakan perintah whatis?
Penggunaan dasar cukup sederhana. Cukup berikan nama alat sebagai masukan, dan whatis akan mencari dan menampilkan deskripsi satu baris untuknya.
Ini contohnya:
whatis ls
Output berikut dihasilkan oleh perintah yang disebutkan di atas:
ls (1) - list directory contents
Q2. Bagaimana cara mendapatkan informasi untuk lebih dari satu perintah?
Ini juga cukup mudah - cukup berikan nama alat sebagai input ke whatis. Berikut ini contohnya:
whatis ls cp rm mv
Dan inilah output yang dihasilkan oleh perintah ini:
ls (1) - list directory contents
cp (1) - copy files and directories
rm (1) - remove files or directories
mv (1) - move (rename) files
Jadi Anda dapat melihat perintah whatis menangani banyak masukan dengan mudah.
Q3. Bisakah kita menggunakan wildcard dengan whatis?
Ya, dimungkinkan untuk menggunakan wildcard dengan perintah whatis. Opsi baris perintah -w mengaktifkan fitur ini.
Ini contohnya;
whatis -w 'who*'
Dan berikut adalah outputnya:
who (1) - show who is logged on
whoami (1) - print effective userid
Q4. Bagaimana cara membuat whatis menghasilkan informasi debug?
Opsi -d membuat perintah whatis menghasilkan informasi debug dalam output. Tak perlu dikatakan, opsi ini terutama untuk pengembang.
Ini contohnya:
whatis -d ls
Dan berikut adalah output yang dihasilkan oleh perintah ini:
From the config file /etc/manpath.config:
Mandatory mandir `/usr/man'.
Mandatory mandir `/usr/share/man'.
Mandatory mandir `/usr/local/share/man'.
Path `/bin' mapped to mandir `/usr/share/man'.
Path `/usr/bin' mapped to mandir `/usr/share/man'.
Path `/sbin' mapped to mandir `/usr/share/man'.
Path `/usr/sbin' mapped to mandir `/usr/share/man'.
Path `/usr/local/bin' mapped to mandir `/usr/local/man'.
Path `/usr/local/bin' mapped to mandir `/usr/local/share/man'.
Path `/usr/local/sbin' mapped to mandir `/usr/local/man'.
Path `/usr/local/sbin' mapped to mandir `/usr/local/share/man'.
Path `/usr/X11R6/bin' mapped to mandir `/usr/X11R6/man'.
Path `/usr/bin/X11' mapped to mandir `/usr/X11R6/man'.
Path `/usr/games' mapped to mandir `/usr/share/man'.
Path `/opt/bin' mapped to mandir `/opt/man'.
Path `/opt/sbin' mapped to mandir `/opt/man'.
Global mandir `/usr/man', catdir `/var/cache/man/fsstnd'.
Global mandir `/usr/share/man', catdir `/var/cache/man'.
Global mandir `/usr/local/man', catdir `/var/cache/man/oldlocal'.
Global mandir `/usr/local/share/man', catdir `/var/cache/man/local'.
Global mandir `/usr/X11R6/man', catdir `/var/cache/man/X11R6'.
Global mandir `/opt/man', catdir `/var/cache/man/opt'.
Added section `1'.
Added section `n'.
Added section `l'.
Added section `8'.
Added section `3'.
Added section `2'.
Added section `3posix'.
Added section `3pm'.
Added section `3perl'.
Added section `3am'.
Added section `5'.
Added section `4'.
Added section `9'.
Added section `6'.
Added section `7'.
`/usr/man' `' `1'
`/usr/share/man' `' `1'
`/usr/local/share/man' `' `1'
`/bin' `/usr/share/man' `0'
`/usr/bin' `/usr/share/man' `0'
`/sbin' `/usr/share/man' `0'
`/usr/sbin' `/usr/share/man' `0'
`/usr/local/bin' `/usr/local/man' `0'
`/usr/local/bin' `/usr/local/share/man' `0'
`/usr/local/sbin' `/usr/local/man' `0'
`/usr/local/sbin' `/usr/local/share/man' `0'
`/usr/X11R6/bin' `/usr/X11R6/man' `0'
`/usr/bin/X11' `/usr/X11R6/man' `0'
`/usr/games' `/usr/share/man' `0'
`/opt/bin' `/opt/man' `0'
`/opt/sbin' `/opt/man' `0'
`/usr/man' `/var/cache/man/fsstnd' `-1'
`/usr/share/man' `/var/cache/man' `-1'
`/usr/local/man' `/var/cache/man/oldlocal' `-1'
`/usr/local/share/man' `/var/cache/man/local' `-1'
`/usr/X11R6/man' `/var/cache/man/X11R6' `-1'
`/opt/man' `/var/cache/man/opt' `-1'
`1' `' `-5'
`n' `' `-5'
`l' `' `-5'
`8' `' `-5'
`3' `' `-5'
`2' `' `-5'
`3posix' `' `-5'
`3pm' `' `-5'
`3perl' `' `-5'
`3am' `' `-5'
`5' `' `-5'
`4' `' `-5'
`9' `' `-5'
`6' `' `-5'
`7' `' `-5'
path directory /usr/local/sbin is in the config file
adding /usr/local/man to manpath
adding /usr/local/share/man to manpath
path directory /usr/local/bin is in the config file
/usr/local/man is already in the manpath
/usr/local/share/man is already in the manpath
path directory /usr/sbin is in the config file
adding /usr/share/man to manpath
path directory /usr/bin is in the config file
/usr/share/man is already in the manpath
path directory /sbin is in the config file
/usr/share/man is already in the manpath
path directory /bin is in the config file
/usr/share/man is already in the manpath
path directory /usr/games is in the config file
/usr/share/man is already in the manpath
path directory /usr/local/games is not in the config file
but does have a ../man, man, ../share/man, or share/man subdirectory
/usr/local/man is already in the manpath
path directory /snap/bin is not in the config file
and doesn't have ../man, man, ../share/man, or share/man subdirectories
adding mandatory man directories
warning: /usr/man: No such file or directory
/usr/share/man is already in the manpath
/usr/local/share/man is already in the manpath
add_nls_manpaths(): processing /usr/local/man:/usr/local/share/man:/usr/share/man
checking for locale en_IN
adding /usr/local/man to manpathlist
adding /usr/local/share/man to manpathlist
adding /usr/share/man to manpathlist
adding /usr/local/man to manpathlist
adding /usr/local/share/man to manpathlist
adding /usr/share/man to manpathlist
Removing duplicate manpath entry /usr/local/share/man (1) -> /usr/local/man (0)
Removing duplicate manpath entry /usr/local/man (2) -> /usr/local/man (0)
Removing duplicate manpath entry /usr/local/share/man (2) -> /usr/local/man (0)
Removing duplicate manpath entry /usr/share/man (2) -> /usr/share/man (1)
final search path = /usr/local/man:/usr/share/man
path=/usr/local/man
warning: can't read the fallback whatis text database /usr/local/man/whatis
path=/usr/share/man
name: ls
sec. ext: 1
section: 1
comp. ext: gz
id: A
mtime: 1516268629.000000000
pointer: -
filter: -
whatis: list directory contents
ls (1) - list directory contents
hashtable_free: 1 entries, 1 (100%) unique
Q5. Bagaimana cara whatis melakukan pencariannya?
Berikut kutipan yang relevan dari halaman manual:
Basis data indeksindex databases are used during the search, and are updated by the
mandb program. Depending on your installation, this may be run by a
periodic cron job, or may need to be run manually after new manual
pages have been installed. To produce an old style text whatis data?
base from the relative index database, issue the command:
whatis -M manpath -w '*' | sort > manpath/whatis
where manpath is a manual page hierarchy such as /usr/man.
Kesimpulan
Jika Anda terlalu banyak menggunakan alat baris perintah Linux, atau pekerjaan sehari-hari Anda melibatkan berurusan dengan halaman manual, perintah whatis mungkin merupakan alat yang berguna untuk Anda. Kami telah membahas beberapa opsi baris perintah whatis di sini. Untuk info lebih lanjut, buka halaman manual alat.