I edited the script here to work with command line
#!/bin/bash## watch a file and scroll## keys => arrow-up/down, page-up/down, pos1, end## usages:# swatch -n <timeout_watch> <file># swatch <file>## version: 1.1# dependencies: awk , tput , clear, read# published: https://unix.stackexchange.com/questions/3842/how-can-i-scroll-within-the-output-of-my-watch-command# gif recording: peek , https://github.com/phw/peek## =============================================# KEYCODES# =============================================# https://unix.stackexchange.com/questions/294908/read-special-keys-in-bash# showkey -a# =============================================# DEFAULTS# =============================================command=""TMPFILE=$(mktemp)line_show_begin=1line_show_begin_last=-1console_lines_correction=4timeout_watch=5timeout_read=.1# =============================================# DEFINE Escape-Sequences# =============================================# http://ascii-table.com/ansi-escape-sequences-vt-100.phpESC_clr_line='\033[K'ESC_reset_screen='\033c'ESC_clr_screen='\033[2J'ESC_cursor_pos='\033[0;0f'ESC_cursor_home='\033[H'# =============================================# FUNCTIONS# =============================================function fn_help() {cat << EOFUsage: ./$0 [-n <timeout>] [<command>] , timeout >0.1s , default 5sEOF}function get_options() { [[ "$1" == "" ]] && { fn_help ; exit 1 ; } while [ -n "$1" ]; do case "$1" in -h|--help) fn_help ;; -n) [[ "$2" == "" ]] && { echo "Error: option -n required <timeout>" ; exit 1 ; } if [[ "$(echo "$2<0.1"|bc)" == "0" ]] ; then timeout_watch="$2" shift else echo "Error: timeout <0.1 not allowed" exit 1 fi ;; -*) echo "Error: unknown option »$1«" exit 1 ;; *) #if [[ -f "$1" ]] ; then command=$1 #else # echo "Error: file not found »$1«" # exit 1 #fi ;; esac shift done [[ "$command" == "" ]] && { echo "Error: command required" ; exit 1 ; }}function fn_print_headline() { hdl_txt_right="${HOSTNAME}: $(date "+%Y-%m-%d %H:%M:%S")" hdl_txt_left="$command , ${timeout_watch}s , $line_show_begin" hdl_txt_left_length=${#hdl_txt_left} printf '%s%*s\n\n'"$hdl_txt_left" "$(($console_columns-$hdl_txt_left_length))" "$hdl_txt_right"}function fn_print_file() { # --------------------------------------------------- # file lenght can change while watch # --------------------------------------------------- eval $command > $TMPFILE lines_command=$(awk 'END {print NR}' $TMPFILE) line_last=$(($lines_command-$console_lines)) (( "$line_last" < "1" )) && { line_last=1; clear; } (( "$line_show_begin" > "$line_last" )) && { line_show_begin=$line_last; clear; } # --------------------------------------------------- # print postion changed # --------------------------------------------------- if (( "$line_show_begin" != "$line_show_begin_last" )) ; then line_show_begin_last=$line_show_begin; clear else printf $ESC_cursor_home fi # --------------------------------------------------- # print file section # --------------------------------------------------- fn_print_headline eval $command > $TMPFILE awk -v var1="$line_show_begin" -v var2="$console_lines" 'NR>=var1 {if (NR>var1+var2) {exit 0} else {printf "%s\n",$0 } }' $TMPFILE}function fn_console_size_change() { console_columns=$(tput cols) console_lines=$(($(tput lines)-$console_lines_correction)) line_show_begin_last=-1}function fn_quit() { echo "quit" $0 , $? setterm -cursor on ; exit 0}# =============================================# GET OPTIONS# =============================================get_options "$@" # pass all arguments with double-quotes# =============================================# INIT TRAP# =============================================trap "fn_console_size_change" SIGWINCH # https://en.wikipedia.org/wiki/Signal_(IPC)#SIGWINCHtrap "fn_quit" INT TERM EXIT# =============================================# MAIN# =============================================fn_console_size_changesetterm -cursor offwhile true ; do fn_print_file read -rsn1 -t $timeout_watch k # char 1 case "$k" in [[:graph:]]) # Normal input handling ;; $'\x09') # TAB # Routine for selecting current item ;; $'\x7f') # Back-Space # Routine for back-space ;; $'\x01') # Ctrl+A # Routine for ctrl+a ;; $'\x1b') # ESC read -rsn1 k # char 2 [[ "$k" == "" ]] && return Esc-Key [[ "$k" == "[" ]] && read -rsn1 -t $timeout_read k # char 3 [[ "$k" == "O" ]] && read -rsn1 -t $timeout_read k # char 3 case "$k" in A) # Arrow-Up-Key (( "$line_show_begin" > "1" )) && line_show_begin=$(($line_show_begin-1)) ;; B) # Arrow-Down-Key (( "$line_show_begin" < "$line_last" )) && line_show_begin=$(($line_show_begin+1)) ;; H) # Pos1-Key line_show_begin=1 ;; F) # End-Key line_show_begin=$line_last ;; 5) # PgUp-Key read -rsn1 -t $timeout_read k # char 4 if [[ "$k" == "~" ]] && (( "$line_show_begin" > "$(($console_lines/2))" )) ; then line_show_begin=$(($line_show_begin-$console_lines/2)) else line_show_begin=1 fi ;; 6) # PgDown-Key read -rsn1 -t $timeout_read k # char 4 if [[ "$k" == "~" ]] && (( "$line_show_begin" < "$(($line_last-$console_lines/2))" )) ; then line_show_begin=$(($line_show_begin+$console_lines/2)) else line_show_begin=$line_last fi ;; esac read -rsn4 -t $timeout_read # Try to flush out other sequences ... ;; esacdone- create a file in ~/bin/cwatch.sh
nano ~/bin/cwatch.sh- change files properties to make it runnable:
chmod +x ~/bin/cwatch.sh- edit ~/.bashrc and add alias
alias cwatch="~/bin/cwatch.sh"now you can try it:
cwatch 'ps aux | grep -v grep'