コマンドライン(CLI)でmanを見よう

ターミナルで通常使っているコマンド「ls」や「cd」「mv」「rm」など、細かくオプションまで把握できていない事に、改めて気がついた。 何気なくlsやcdなどは使っているが、「-a」程度であれば、おまじないのように覚えているのだが、他にどういうオプションがあるかは正直あまり深く語れない。 そこで、「man」コマンドを叩いてみた。 $ man ls NAME ls - list directory contents SYNOPSIS ls [OPTION]... [FILE]... DESCRIPTION List information about the FILEs (the current directory by default). Sort entries alphabetically if none of -cftuvSUX nor --sort is specified. Mandatory arguments to long options are mandatory for short options too. -a, --all do not ignore entries starting with . -A, --almost-all do not list implied . and .. --author with -l, print the author of each file -b, --escape print C-style escapes for nongraphic characters --block-size=SIZE scale sizes by SIZE before printing them; e.g., '--block-size=M' prints sizes in units of 1,048,576 bytes; see SIZE format below -B, --ignore-backups do not list implied entries ending with ~ -c with -lt: sort by, and show, ctime (time of last modification of file status information); with -l: show ctime and sort by name; otherwise: sort by ctime, newest first -C list entries by columns --color[=WHEN] colorize the output; WHEN can be 'never', 'auto', or 'always' (the default); more info below -C list entries by columns --color[=WHEN] colorize the output; WHEN can be 'never', 'auto', or 'always' (the default); more info below -d, --directory list directories themselves, not their contents -D, --dired generate output designed for Emacs' dired mode -f do not sort, enable -aU, disable -ls --color -F, --classify append indicator (one of */=>@|) to entries --file-type likewise, except do not append '*' --format=WORD across -x, commas -m, horizontal -x, long -l, single-column -1, verbose -l, vertical -C --full-time like -l --time-style=full-iso -g like -l, but do not list owner --group-directories-first group directories before files; can be augmented with a --sort option, but any use of --sort=none (-U) disables grouping -G, --no-group in a long listing, don't print group names -h, --human-readable with -l and/or -s, print human readable sizes (e.g., 1K 234M 2G) --si likewise, but use powers of 1000 not 1024 -H, --dereference-command-line follow symbolic links listed on the command line --dereference-command-line-symlink-to-dir follow each command line symbolic link that points to a directory --hide=PATTERN do not list implied entries matching shell PATTERN (overridden by -a or -A) --indicator-style=WORD append indicator with style WORD to entry names: none (default), slash (-p), file-type (--file-type), classify (-F) -i, --inode print the index number of each file -I, --ignore=PATTERN do not list implied entries matching shell PATTERN -k, --kibibytes default to 1024-byte blocks for disk usage -l use a long listing format -L, --dereference when showing file information for a symbolic link, show information for the file the link references rather than for the link itself -m fill width with a comma separated list of entries -n, --numeric-uid-gid like -l, but list numeric user and group IDs -N, --literal print raw entry names (don't treat e.g. control characters specially) -o like -l, but do not list group information -p, --indicator-style=slash append / indicator to directories -q, --hide-control-chars print ? instead of nongraphic characters --show-control-chars show nongraphic characters as-is (the default, unless program is 'ls' and output is a terminal) -Q, --quote-name enclose entry names in double quotes --quoting-style=WORD use quoting style WORD for entry names: literal, locale, shell, shell-always, c, escape -r, --reverse reverse order while sorting -R, --recursive list subdirectories recursively -s, --size print the allocated size of each file, in blocks -S sort by file size --sort=WORD sort by WORD instead of name: none (-U), size (-S), time (-t), version (-v), extension (-X) --time=WORD with -l, show time as WORD instead of default modification time: atime or access or use (-u) ctime or status (-c); also use specified time as sort key if --sort=time --time-style=STYLE with -l, show times using style STYLE: full-iso, long-iso, iso, locale, or +FORMAT; FORMAT is inter‐ preted like in 'date'; if FORMAT is FORMAT1<newline>FORMAT2, then FORMAT1 applies to non-recent files and FORMAT2 to recent files; if STYLE is prefixed with 'posix-', STYLE takes effect only outside the POSIX locale -t sort by modification time, newest first -T, --tabsize=COLS assume tab stops at each COLS instead of 8 -u with -lt: sort by, and show, access time; with -l: show access time and sort by name; otherwise: sort by access time -U do not sort; list entries in directory order -v natural sort of (version) numbers within text -w, --width=COLS assume screen width instead of current value -x list entries by lines instead of by columns -X sort alphabetically by entry extension -Z, --context print any security context of each file -1 list one file per line --help display this help and exit --version output version information and exit The SIZE argument is an integer and optional unit (example: 10K is 10*1024). Units are K,M,G,T,P,E,Z,Y (powers of 1024) or KB,MB,... (powers of 1000). Using color to distinguish file types is disabled both by default and with --color=never. With --color=auto, ls emits color codes only when standard output is connected to a terminal. The LS_COLORS environment variable can change the settings. Use the dircolors command to set it. Exit status: 0 if OK, 1 if minor problems (e.g., cannot access subdirectory), 2 if serious trouble (e.g., cannot access command-line argument). GNU coreutils online help: <http: //www.gnu.org/software/coreutils> Report ls translation bugs to <http: //translationproject.org/team> AUTHOR Written by Richard M. Stallman and David MacKenzie. COPYRIGHT Copyright © 2014 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later <http: //gnu.org/licenses/gpl.html>. This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent per‐ mitted by law. SEE ALSO The full documentation for ls is maintained as a Texinfo manual. If the info and ls programs are properly installed at your site, the command info coreutils 'ls invocation' should give you access to the complete manual. びっくりすることに、lsコマンドで、このボリュームが返ってくる。 オプションの多さにも正直びっくりする。 ドキュメントの重要性も改めて感じたが、機能の仕様についても、考えさせられる。 もしかしたら、manコマンドは、ドキュメント、仕様の見本じゃないかと思った。 是非、色々と詳細を熟読して、内容を把握してみたくなった。 ビジネス文庫読んでる場合じゃないぞ！！！