# [2]
# print commands to be executed to `stderr` before any substitution and expansion is applied
set -v
# print everything as if it were executed, after any substitution and expansion is applied
# `+` is prepended to indicate the depth-level
set -x
# to exit these modes
set +v
set +x

# the prompt and commnads may not display correctly on remote machine you SSH to
# use the following command to correct it
resize

# list the dependent shared libraries [3]
ldd <executable>
# if some libraries are missing, add to LD_LIBRARY_PATH
export LD_LIBRARY_PATH=<path_to_search_for_library>

# tar familty **********
# compress a dir to .tar.gz file [4]
tar -czvf <archieve>.tar.gz <path-to-dir>
# extract from .tgz file
# -x: extract, -v: verbose, -z: gnnuzip, -f: last falg just before the file
tar -xvzf <file.tgz>
# zip familty **********
# zip to path specified by -d 
zip -d <path-to-.zip> <file(s)>
# unzip to a path
unzip <.zip-file> -d [<path-to-unzip>]

# redirect stdout and stderr to seperate files
<cmd> > stdout.log 2> stderr.log
# redirect both stdout and stderr to one file
<cmd> &> stdout_err.log

# python version [5], other versiions are on available [5]
command | python -c 'import sys,time;sys.stdout.write("".join(( " ".join((time.strftime("[%Y-%m-%d %H:%M:%S]", time.localtime()), line)) for line in sys.stdin )))'

# search for file name recursively in a dir
find <dir-path> -name "name-to-search"
find ./ -name "foo*.txt"
# search for file contents recursively in a dir
grep -r "string-to-search" *
# search for file contents recursively in a dir (only certain files)
grep --include=\*.{cpp,h} -r <path-to-search> -e "pattern-to-search"

# traverse a range [6]
for i in {0..99}; do cat min_${i}.txt | wc -l; done
for ((i=0; i<100; i+=1)); do cat min_${i}.txt | wc -l; done
# traverse on files
for i in *.txt; do mv ${i}_backup.txt; done

# redirect the comamnd block to stdin of the COMMAND
COMMAND <<LimitString
command #1
command #2
...
LimitString
# Equivalent to
COMMAND < command-file
# where command-file contains 
command #1
command #2
...

$ strace -eopen,read -f -o /tmp/ssh-strace.txt ssh <some-hostname>

# Sessions: workspace
tmux # start a new session
tmux new -s NAME # specify the NAME to start
tmux ls # lists all curretn sessions
tmux a # attach the last session
tmux a -t NAME # attach the NAME session
tmux a -t NAME -d # attach the NAME session, detach any other clients (to resize the window)
<C-b> d # detach the current session
<C-d> # close the Panel
exit # close the Panel
# Windows: tabs
<C-b> c # create a new windows within the session
<C-b> N # go to the Nth window
<C-b> n # go to the next window
<C-b> p # go to the previous window
<C-b> , # rename the current window
<C-b> w # list current windows
# Panes: splits
<C-b> <quote> # split horizontally
<C-b> % # split vertically
<C-b> <up,down,left,right> # move focus to the direction
<C-b>+<up,down,left,right> # resize current pane to the direction
<C-b> z # zoom in or zoom out of current pane
<C-b> <space> # traverse pane arrangements
<C-b> [ # scroll up and down using <page-up> and <page-down>

# copy in tmux [1]
# default method
<C-b> [ # 1. enter copy mode
<page-up> <page-down> <arrow> # 2. navigate to where you want to copy
<C-space> # 3. start copy
<arrow> # 4. select what to copy
<C-w> # 5 copy to `tmux` buffer
<C-b> ] # paste using `tmux` buffer
# vi mode: modify ~/.tmux.conf and use v, y, p
# mouse mode: add following to ~/.tmux.conf
set -g mouse on
# then, use <C-b> [ to enter copy mode, use mouse to select and <C-c> to copy as normal
# q to quit copy mode, and right click mouse to paste