pager program like less, able to repeat top N lines
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 $what
Make the script executable with chmod +x ~/bin/vimpager
.
Third, you need to override pager program for psql. Do not set variable PAGER
globally, as it can affect other programs, not only psql. Instead, add this to your ~/.psqlrc
file:
\setenv PAGER ~/bin/vimpager
Voila! After reloading your profile, you can enjoy the result, which should behave as expected (arrow keys browse both vertically and horizontally) and look like this: . Plus, all the power of Vim is right there if you need it.
Have you tried SQL Mode in Emacs/XEmacs?
It's certainly not as simple to use as more
or less
, but it does what your asking for, leaving a header row while scrolling results vertically and horizontally.
This borrows very heavily from the accepted answer, but adds...
- Faster scrolling
- Cannot accidentally scroll into the header
- Syntax highlighting (some credit belongs here)
- Positive/negative numbers, dates, times,
NULL
, True/False (and T/F, Y/N, Yes/No) - Row numbers, if you have them before a pipe char.
- Positive/negative numbers, dates, times,
- Help text
- Support for the Vim that is included with Git for Windows
- Do not threaten to update the view if the stdin buffer changes
Some portions may have to be tweaked for your specific output, since I do not use psql
. I also have slightly different helper functions for my purposes, but they are similar to those in the accepted answer.
Sample input
| ID | First | Last | Member | Balance |
--+----+-----------+--------------+--------+---------+
1| 4 | Tom | Hanks | False | 0.00 |
2| 12 | Susan | Patterson | True | 10.00 |
3| 23 | Harriet | Langford-Wat | False | 0.00 |
4| 8 | Jerry | NULL | True | -382.94 |
[… More rows …]
10| 87 | Horace | Weaver | False | 47.52 |
Code
" :HeadPager
" Turn vim into a pager with a header row
" Adapted from https://unix.stackexchange.com/a/27840/143088
fun! HeadPager()
" If you didn't get three lines, shortcut out
if line('$') < 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()