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Text File | 1988-04-28 | 14.9 KB | 463 lines

_l_e_s_s - _o_p_p_o_s_i_t_e _o_f _m_o_r_e _l_e_s_s [-_d_s_t_w_c_C_e_E_m_M_q_Q_u_U] [-_h_N] [-b[fp]_N] [-x_N] [-[z]_N] [-_P[_m_M]_s_t_r_i_n_g] [-[lL]_l_o_g_f_i_l_e] [+_c_m_d] [_f_i_l_e_n_a_m_e]... _L_e_s_s is a program similar to _m_o_r_e (1), but which allows backwards movement in the file as well as forward movement. Also, _l_e_s_s does not have to read the entire input file before starting, so with large input files it starts up fas- ter than text editors like _v_i (1). _L_e_s_s uses termcap, so it can run on a variety of terminals. There is even limited support for hardcopy terminals. (On a hardcopy terminal, lines which should be printed at the top of the screen are prefixed with an up-arrow.) Commands are based on both _m_o_r_e and _v_i. Commands may be preceeded by a decimal number, called N in the descrip- tions below. The number is used by some commands, as indi- cated. _I_n _t_h_e _f_o_l_l_o_w_i_n_g _d_e_s_c_r_i_p_t_i_o_n_s, ^_X _m_e_a_n_s _c_o_n_t_r_o_l-_X. H Help: display a summary of these commands. If you for- get all the other commands, remember this one. SPACEScroll forward N lines, default one window (see option -z below). If N is more than the screen size, only the final screenful is displayed. f or ^F Same as SPACE. b or ^B Scroll backward N lines, default one window (see option -z below). If N is more than the screen size, only the final screenful is displayed. RETURNScroll forward N lines, default 1. The entire N lines are displayed, even if N is more than the screen size. e or ^E Same as RETURN. j or ^J Also the same as RETURN. July 5, 1988 - 2 - y or ^Y Scroll backward N lines, default 1. The entire N lines are displayed, even if N is more than the screen size. k or ^K Same as y. d or ^D Scroll forward N lines, default 10. If N is specified, it becomes the new default for subsequent d and u com- mands. u or ^U Scroll backward N lines, default 10. If N is speci- fied, it becomes the new default for subsequent d and u commands. r or ^R or ^L Repaint the screen. R Repaint the screen, discarding any buffered input. Useful if the file is changing while it is being viewed. g Go to line N in the file, default 1 (beginning of file). (Warning: this may be slow if N is large.) G Go to line N in the file, default the end of the file. (Warning: this may be slow if standard input, rather than a file, is being read.) p Go to a position N percent into the file. N should be between 0 and 100. (This is possible if standard input is being read, but only if _l_e_s_s has already read to the end of the file. It is always fast, but not always useful.) % Same as p. m Followed by any lowercase letter, marks the current position with that letter. ' (Single quote.) Followed by any lowercase letter, returns to the position which was previously marked July 5, 1988 - 3 - with that letter. Followed by another single quote, returns to the postion at which the last "large" move- ment command was executed. All marks are lost when a new file is examined. /pattern Search forward in the file for the N-th line containing the pattern. N defaults to 1. The pattern is a regu- lar expression, as recognized by _e_d. The search starts at the second line displayed (but see the -t option, which changes this). ?pattern Search backward in the file for the N-th line contain- ing the pattern. The search starts at the line immedi- ately before the top line displayed. n Repeat previous search, for N-th line containing the last pattern. E Examine a new file. If the filename is missing, the "current" file (see the N and P commands below) from the list of files in the command line is re-examined. If the filename is a pound sign (#), the previously examined file is re-examined. N Examine the next file (from the list of files given in the command line). If a number N is specified (not to be confused with the command N), the N-th next file is examined. P Examine the previous file. If a number N is specified, the N-th previous file is examined. = or ^G Prints some information about the file being viewed, including its name and the byte offset of the bottom line being displayed. If possible, it also prints the length of the file and the percent of the file above the last displayed line. - Followed by one of the command line option letters (see below), this will toggle the setting of that option and print a message describing the new setting. July 5, 1988 - 4 - +cmd Causes the specified cmd to be executed each time a new file is examined. For example, +G causes _l_e_s_s to ini- tially display each file starting at the end rather than the beginning. V Prints the version number of _l_e_s_s being run. q Exits _l_e_s_s. The following two commands may or may not be valid, depending on your particular installation. v Invokes an editor to edit the current file being viewed. The editor is taken from the environment vari- able EDITOR, or defaults to "vi". ! shell-command Invokes a shell to run the shell-command given. A per- cent sign in the command is replaced by the name of the current file. "!!" repeats the last shell command. _C_o_m_m_a_n_d _l_i_n_e _o_p_t_i_o_n_s _a_r_e _d_e_s_c_r_i_b_e_d _b_e_l_o_w. _M_o_s_t _o_p_t_i_o_n_s _m_a_y _b_e _c_h_a_n_g_e_d _w_h_i_l_e _l_e_s_s is running, via the "-" command. Options are also taken from the environment variable "LESS". For example, if you like more-style prompting, to avoid typing "less -m ..." each time _l_e_s_s is invoked, you might tell _c_s_h: setenv LESS m or if you use _s_h: LESS=m; export LESS The environment variable is parsed before the command line, so command line options override the LESS environment vari- able. A dollar sign ($) may be used to signal the end of an option string. This is important only for options like -P which take a following string. -b The -b_n option tells _l_e_s_s to use a non-standard buffer size. There are two standard (default) buffer sizes, one is used when a file is being read and the other when a pipe (standard input) is being read. The current defaults are 5 buffers for files and 12 for pipes. (Buffers are 1024 bytes.) The number _n speci- fies a different number of buffers to use. The -b may be followed by "f", in which case only the file default July 5, 1988 - 5 - is changed, or by "p" in which case only the pipe default is changed. Otherwise, both are changed. -c Normally, _l_e_s_s will repaint the screen by scrolling from the bottom of the screen. If the -c option is set, when _l_e_s_s needs to change the entire display, it will paint from the top line down. -C The -C option is like -c, but the screen is cleared before it is repainted. -d Normally, _l_e_s_s will complain if the terminal is dumb; that is, lacks some important capability, such as the ability to clear the screen or scroll backwards. The -d option suppresses this complaint (but does not oth- erwise change the behavior of the program on a dumb terminal). -e Normally the only way to exit less is via the "q" com- mand. The -e option tells less to automatically exit the second time it reaches end-of-file. -E The -E flag causes less to exit the first time it reaches end-of-file. -h Normally, _l_e_s_s will scroll backwards when backwards movement is necessary. The -h option specifies a max- imum number of lines to scroll backwards. If it is necessary to move backwards more than this many lines, the screen is repainted in a forward direction. (If the terminal does not have the ability to scroll back- wards, -h0 is implied.) -l The -l option, followed immediately by a filename, will cause _l_e_s_s to copy its input to the named file as it is being viewed. This applies only when the input file is a pipe, not an ordinary file. If the file already exists, less will ask for confirmation before overwrit- ing it. -L The -L option is like -l, but it will overwrite an existing file without asking for confirmation. -m Normally, _l_e_s_s prompts with a colon. The -m option causes _l_e_s_s to prompt verbosely (like _m_o_r_e), with the percent into the file. -M The -M option causes _l_e_s_s to prompt even more verbosely than _m_o_r_e. -P The -P option provides a way to tailor the three prompt styles to your own preference. You would normally put this option in your LESS environment variable, rather than type it in with each less command. Such an option July 5, 1988 - 6 - must either be the last option in the LESS variable, or be terminated by a dollar sign. -P followed by a string changes the default (short) prompt to that string. -Pm changes the medium (-m) prompt to the string, and -PM changes the long (-M) prompt. The string consists of a sequence of letters which are replaced with certain predefined strings, as follows: Ffile name ffile name, only once Ofile n of n ofile n of n, only once bbyte offset ppercent into file Ppercent if known, else byte offset Angle brackets, < and >, may be used to surround a literal string to be included in the prompt. The defaults are "fo" for the short prompt, "foP" for the medium prompt, and "Fobp" for the long prompt. Example: Setting your LESS variable to "PmFOP$PMFObp" would change the medium and long prompts to always include the file name and "file n of n" message. Another example: Setting your LESS variable to "mPm<--Less-->FoPe" would change the medium prompt to the string "--Less--" followed by the file name and percent into the file. It also selects the medium prompt as the default prompt (because of the first "m"). -q Normally, if an attempt is made to scroll past the end of the file or before the beginning of the file, the terminal bell is rung to indicate this fact. The -q option tells _l_e_s_s not to ring the bell at such times. If the terminal has a "visual bell", it is used instead. -Q Even if -q is given, _l_e_s_s will ring the bell on certain other errors, such as typing an invalid character. The -Q option tells _l_e_s_s to be quiet all the time; that is, never ring the terminal bell. If the terminal has a "visual bell", it is used instead. -s The -s option causes consecutive blank lines to be squeezed into a single blank line. This is useful when viewing _n_r_o_f_f output. -t Normally, forward searches start just after the top displayed line (that is, at the second displayed line). Thus forward searches include the currently displayed screen. The -t option causes forward searches to start just after the bottom line displayed, thus skipping the currently displayed screen. -u If the -u option is given, backspaces are treated as printable characters; that is, they are sent to the July 5, 1988 - 7 - terminal when they appear in the input. -U If the -U option is given, backspaces are printed as the two character sequence "^H". If neither -u nor -U is given, backspaces which appear adjacent to an underscore character are treated spe- cially: the underlined text is displayed using the terminal's hardware underlining capability. Also, backspaces which appear between two identical charac- ters are treated specially: the overstruck text is printed using the terminal's hardware boldface capabil- ity. Other backspaces are deleted, along with the preceeding character. -w Normally, _l_e_s_s uses a tilde character to represent lines past the end of the file. The -w option causes blank lines to be used instead. -x The -x_n option sets tab stops every _n positions. The default for _n is 8. -[z] When given a backwards or forwards window command, _l_e_s_s will by default scroll backwards or forwards one screenful of lines. The -z_n option changes the default scrolling window size to _n lines. If _n is greater than the screen size, the scrolling window size will be set to one screenful. Note that the "z" is optional for compatibility with _m_o_r_e. + If a command line option begins with +, the remainder of that option is taken to be an initial command to _l_e_s_s. For example, +G tells _l_e_s_s to start at the end of the file rather than the beginning, and +/xyz tells it to start at the first occurence of "xyz" in the file. As a special case, +<number> acts like +<number>g; that is, it starts the display at the specified line number (however, see the caveat under the "g" command above). If the option starts with ++, the initial command applies to every file being viewed, not just the first one. The + command described previ- ously may also be used to set (or change) an initial command for every file. _W_h_e_n _u_s_e_d _o_n _s_t_a_n_d_a_r_d _i_n_p_u_t (_r_a_t_h_e_r _t_h_a_n _a _f_i_l_e), _y_o_u _c_a_n _m_o_v_e _b_a_c_k_w_a_r_d_s _o_n_l_y _a _f_i_n_i_t_e _a_m_o_u_n_t, _c_o_r_r_e_s_p_o_n_d_i_n_g _t_o _t_h_a_t _p_o_r_t_i_o_n _o_f _t_h_e _f_i_l_e _w_h_i_c_h _i_s _s_t_i_l_l _b_u_f_f_e_r_e_d. _T_h_e -_b _o_p_t_i_o_n _m_a_y _b_e _u_s_e_d _t_o _e_x_p_a_n_d _t_h_e _b_u_f_f_e_r _s_p_a_c_e. July 5, 1988