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Is there any way to make less program repeat first line (or first 2 lines) on every displayed page?

Is there any other pager program which can do this?

This would be a killer-app for database table browsing, think mysql or psql or gqlplus...

See the screenshot.

Console pager for psql output

I want to repeat header line + horizontal ascii bar.

Identically as the "Freeze Top N Rows" feature known from spreadsheet software.

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    Oh boy, that asks for an extension to less, like a Freeze Pane point. For example --freeze-pane 10,2 would keep 1 line of column headers and 10 columns row header. Horizontal and vertical scrolling would preserve the row and column headers respectively. That would be really cool to use for a psql pager (merlinmoncure.blogspot.com/2007/10/better-psql-with-less.html) Commented Jan 17, 2020 at 19:20
  • The link in the question seems to be no longer accessible. I get a "Sign in to access this site" dialog if try and follow the link. web.archive.org/web/20120121103942/http://… is an archived version of the page, but that doesn't display any images. I realize this is an old question, but if possible can you edit to embed the screenshot? Commented May 10 at 17:54
  • @chester-gillon Voila! I am the author of both the question and the answer so nothing easier than just uploading my screenshot again :-) Commented May 16 at 15:28

8 Answers 8

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There is a solution using Vim.

First, you need a Vim macro, which will do most of the work. Save it in ~/.vim/plugin/less.vim:

" :Less " turn vim into a pager for psql aligned results fun! Less() set nocompatible set nowrap set scrollopt=hor set scrollbind set number execute 'above split' " resize upper window to one line; two lines are not needed because vim adds separating line execute 'resize 1' " switch to lower window and scroll 2 lines down wincmd j execute 'norm! 2^E' " hide statusline in lower window set laststatus=0 " hide contents of upper statusline. editor note: do not remove trailing spaces in next line! set statusline=\ " arrows do scrolling instead of moving nmap ^[OC zL nmap ^[OB ^E nmap ^[OD zH nmap ^[OA ^Y nmap <Space> <PageDown> " faster quit (I tend to forget about the upper panel) nmap q :qa^M nmap Q :qa^M endfun command! -nargs=0 Less call Less()

Second, to emulate a pager, you need to invoke vim so that it will:

  • read standard input
  • but if argument is given on command line, read whatever comes there
  • work in read-only mode
  • skip all init scripts, but instead execute Less macro defined above

I put this together as helper script in ~/bin/vimpager:

#!/bin/bash what=- test "$@" && what="$@" exec vim -u NONE -R -S ~/.vim/plugin/less.vim -c Less $what

Make the script executable with chmod +x ~/bin/vimpager.

Third, you need to override pager program for psql. Do not set variable PAGER globally, as it can affect other programs, not only psql. Instead, add this to your ~/.psqlrc file:

\setenv PAGER ~/bin/vimpager

Voila! After reloading your profile, you can enjoy the result, which should behave as expected (arrow keys browse both vertically and horizontally) and look like this: vimpager in action. Plus, all the power of Vim is right there if you need it.

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  • This is lovely, I tried it. Now it would be nice if one could add row headers also, instead of these row numbers. Commented Jan 17, 2020 at 19:27
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Have you tried SQL Mode in Emacs/XEmacs?

It's certainly not as simple to use as more or less, but it does what your asking for, leaving a header row while scrolling results vertically and horizontally.

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  • Thanks, I don't know Emacs but it sound interesting. I would eventually need a shell script which would: start emacs, run psql there, (with given conn. params), enable sql-mode and do what I want (always freeze top 2 rows when there are query results larger than screen size). any hints on that? Commented Dec 28, 2011 at 14:03
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This borrows very heavily from the accepted answer, but adds...

  • Faster scrolling
  • Cannot accidentally scroll into the header
  • Syntax highlighting (some credit belongs here)
    • Positive/negative numbers, dates, times, NULL, True/False (and T/F, Y/N, Yes/No)
    • Row numbers, if you have them before a pipe char.
  • Help text
  • Support for the Vim that is included with Git for Windows
  • Do not threaten to update the view if the stdin buffer changes

Some portions may have to be tweaked for your specific output, since I do not use psql. I also have slightly different helper functions for my purposes, but they are similar to those in the accepted answer.

Sample input

 | ID | First | Last | Member | Balance | --+----+-----------+--------------+--------+---------+ 1| 4 | Tom | Hanks | False | 0.00 | 2| 12 | Susan | Patterson | True | 10.00 | 3| 23 | Harriet | Langford-Wat | False | 0.00 | 4| 8 | Jerry | NULL | True | -382.94 | [… More rows …] 10| 87 | Horace | Weaver | False | 47.52 |

Code

" :HeadPager " Turn vim into a pager with a header row " Adapted from https://unix.stackexchange.com/a/27840/143088 fun! HeadPager() " If you didn't get three lines, shortcut out if line('$') < 3 set nocompatible nmap <silent> q :qa!<c-M> nmap <silent> Q :qa!<c-M> return endif set noswapfile set nocompatible set nowrap set scrollopt=hor set scrollbind " Hide statusline in lower window set laststatus=0 " Explain mapped chars in status line. set statusline=\ \ \ Q\ to\ quit\.\ Arrows\ or\ mousewheel\ to\ scroll\.\ \(Vim\ commands\ work\,\ too\.\) " Delete/copy header lines silent execute '1,2d' " Split screen with new buffer (opens at top) execute 'new' " Switch to upper split wincmd k " Paste the header over the blank line execute 'norm! Vp' " Header highlighting syn match Pipe "|" hi def Pipe ctermfg=blue syn match Any /[^|]\+/ hi def Any ctermfg=yellow " Switch back to lower split for scrolling wincmd j " Set lower split height to maximum execute "norm! \<c-W>_" " Syntax highlighting syn cluster CellContents contains=None syn match Pipe "|" contained nextgroup=@CellContents skipwhite hi def Pipe ctermfg=blue " Start with newline or |. End right before next | or EOL syn region Cell start=/\v(^|\|)\s*/ end=/\v(\||$)\@=/ contains=LineNumber,Pipe syn match NumPos /\v\+?\d+(,?\d{3})*\.?\d*\ze *(\||$)\@=/ contained syn match NumNeg /\v-\d+(,?\d{3})*\.?\d*\ze *(\||$)\@=/ contained syn match NumZero /\v[+-]?0+\.?0*\ze *(\||$)\@=/ contained hi def NumPos ctermfg=cyan hi def NumNeg ctermfg=red hi def NumZero ctermfg=NONE syn cluster CellContents add=NumPos,NumNeg,NumZero syn match DateVal /\v\d{4}-\d{2}-\d{2}/ contained nextgroup=TimeVal skipwhite syn match TimeVal /\v\d{1,2}:\d{2}(:\d{2})?(\.\d+)?(Z| ?\c[AP]M)?\ze *(\||$)\@=/ contained hi def DateVal ctermfg=magenta hi def TimeVal ctermfg=magenta syn cluster CellContents add=DateVal,TimeVal syn match TrueVal /\v\c(t(rue)?|y(es)?)\ze *(\||$)\@=/ contained syn match FalseVal /\v\c(f(alse)?|no?)\ze *(\||$)\@=/ contained hi def TrueVal ctermfg=green hi def FalseVal ctermfg=red syn match NullVal /\v\cnull?\ze *(\||$)\@=/ contained hi def NullVal ctermbg=gray ctermfg=black syn cluster CellContents add=TrueVal,FalseVal,NullVal syn match LineNumber /^ *\d\+/ contained hi def LineNumber ctermfg=yellow " Arrows do scrolling instead of moving nmap <silent> <Up> 3<c-Y> nmap <silent> <Down> 3<c-E> nmap <silent> <Left> zH nmap <silent> <Right> zL nmap <Space> <PageDown> " Faster quit (I tend to forget about the upper panel) nmap <silent> q :qa!<c-M> nmap <silent> Q :qa!<c-M> " Ignore external updates to the buffer autocmd! FileChangedShell */fd/* autocmd! FileChangedRO */fd/* endfun command! -nargs=0 HeadPager call HeadPager()
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There's a new --header option added to less at version 600 in 2022 or so, wherein you can freeze the top set of lines.

--header=L,C,N

Sets the number of header lines and columns displayed on the screen. The number of header lines is set to L. If L is 0, header lines are disabled. If L is empty or missing, the number of header lines is unchanged. The number of header columns is set to C. If C is 0, header columns are disabled. If C is empty or missing, the number of header columns is unchanged. The first header line is set to line number N in the file. If N is empty or missing, it is taken to be the number of the line currently displayed in the first line of the screen (if the --header command has been issued from within less), or 1 (if the --header option has been given on the command line). The special form "--header=-" disables header lines and header columns, and is equivalent to "--header=0,0".

When L is nonzero, the first L lines at the top of the screen are replaced with the L lines of the file beginning at line N, regardless of what part of the file is being viewed. When header lines are displayed, any file contents before the header line cannot be viewed. When C is nonzero, the first C characters displayed at the beginning of each line are replaced with the first C characters of the line, even if the rest of the line is scrolled horizontally.

In short: L is top lines to freeze, C is left columns to freeze, and N is top lines to skip before starting the L lines.

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    Great news! Unfortunately less 600+ it's still not included in Ubuntu LTS (version 590 there) but for future this will be the way to go. Thank you for sharing. Commented Apr 11 at 14:16
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You could use multiple 'regions' in screen:

$ cat screenrc.sql escape ^aa # adjust as needed bind q quit # to quickly exit screen 0 less ${FILE} screen 1 less ${FILE} split # create two regions focus top # starting with the top region resize 4 # make it four lines (one for screen line, one for less prompt) select 0 # display window 0 focus bottom # in the bottom region select 1 # display window 1 and focus here

Then you just need to set the $FILE environment variable:

$ FILE=$HOME/.bash_profile screen -mc screenrc.sql
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    this is almost what I wanted, but (a) the top window does not scroll right, so it is useless for wide tables Commented Dec 28, 2011 at 19:53
  • Not sure what you mean by 'useless for wide tables'; screen can expand to the size of the terminal (if it doesn't run the fit screen command). I had thought that you didn't want the top to scroll. When I tested it on my own, both windows scroll as they should. The top scrolls two lines (1-2, 3-4, 5-6, etc.) and the bottom scrolls as needed. What is the behavior you are seeing/ Commented Dec 28, 2011 at 20:05
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You can use fzf as a pager and freeze as many lines from the top as you wish while scrolling through the file. Here is an example which you can edit to your taste:

echo <your_filename> | fzf --preview='echo {};cat {}' --preview-window='90%,~1'

This command freezes filename (on line 1) using ~1 option; change to bigger number as needed.

You can scroll using mouse (or ctrl-up/down or ctrl )

And of course you can search as usual.

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You can add a number before the 'forward' and it will scroll N lines, not a full length. So if your terminal window is 40 lines, type 38f to start scrolling only 38 lines, leaving the last 2 line from the last 'page.' From the manpage:

 SPACE or ^V or f or ^F Scroll forward N lines, default one window (see option -z below). If N is more than the screen size, only the final screenful is displayed. Warning: some systems use ^V as a spe‐ cial literalization character. z Like SPACE, but if N is specified, it becomes the new window size. b or ^B or ESC-v 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.
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    I need to keep first, not last N lines. As "freeze top N rows" in Google Spreadsheet. Commented Dec 28, 2011 at 13:29
  • Ah, sorry. I don't know if a utility that would do that. Then what I suggest is: use screen or tmux to create two panes, resize of the first one to two lines (resize 2) and then run less, in the second pane, run less normally. You could set this up as a script with a specific .screenrc file. See alternate answer. Commented Dec 28, 2011 at 14:14
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For viewing tables (comma, semicolon or tab separated) you could try csvlens available from GitHub at https://github.com/YS-L/csvlens. It freezes the top row as you scroll. You can change the delimiter when you launch the app. To test it you could simply download the executable which is very small (8.7MB) and ready to use. The documentation is not great but you can get all the help you need by pressing H or ? keys when inside the app. It is blisteringly fast and great for viewing tables with lots of fields as you can scroll horizontally from field to field. You can even freeze groups of fields while you scroll horizontally. Well worth a try.

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