Linux | Terminal Command

Linux

# -m displays percentages
# -N displays line numbers
# -i ignores case when searching
# h Display the help interface
# Q quits less command
less -miN file # alias less='less -miN'

sh run.sh | tee output.txt
# If you want to print the error output to the screen and the file at the same time
sh run.sh 2>&1 | tee lsls.log

sh run.sh >/dev/null 2>&1 &

# -C : Print Around Lines
grep -irn -C 3 "xxx" file
grep -irn -C 3 "xxx" ./*
grep -irn 'pattern1\|pattern2' fileName_or_filePath

find ./ -name "xxx"
find - L ./ -name "xxx" # -L :Follow symbolic links
find ./ -type f | wc -l # count how many files
find ./ -size +1M       # large 1MB size

ldd xxx

rename IMG img IMG* # IMG001.jpg to img001.jpg

Find & Delete

# Find files smaller than 100M: -print or -delete
find . -type f -name "*.nc" -size -100M -print
find . -type f -name "*.nc" -size -100M -delete

# Find files larger than 100M: -print or -delete
find . -type f -name "*.nc" -size +100M -print
find . -type f -name "*.nc" -size +100M -delete

# if your "find" does not support delete:
find . -type f ! -name '*.mp3' ! -name '*.mp4' -size +1M -exec rm {} \;

For client node,

• create a file .info on home directory
• copy all below into .info
• drectly source .info or write source .info into .bashrc

How can I display the absolute path in bash prompt?

• https://superuser.com/questions/202212/how-can-i-display-the-absolute-path-in-bash-prompt

export PS1="\[\`if [[ \$? = "0" ]]; then echo '\e[32m\h\e[0m'; else echo '\e[31m\h\e[0m' ; fi\`:\`pwd\`\n\$ "

better is,

# set a fancy prompt (non-color, unless we know we "want" color)
case "$TERM" in
    xterm-color|*-256color) color_prompt=yes;;
esac

# uncomment for a colored prompt, if the terminal has the capability; turned
# off by default to not distract the user: the focus in a terminal window
# should be on the output of commands, not on the prompt
#force_color_prompt=yes

if [ -n "$force_color_prompt" ]; then
    if [ -x /usr/bin/tput ] && tput setaf 1 >&/dev/null; then
	# We have color support; assume it's compliant with Ecma-48
	# (ISO/IEC-6429). (Lack of such support is extremely rare, and such
	# a case would tend to support setf rather than setaf.)
	color_prompt=yes
    else
	color_prompt=
    fi
fi

if [ "$color_prompt" = yes ]; then
    PS1='${debian_chroot:+($debian_chroot)}\[\033[01;32m\]\u@\h\[\033[00m\]:\[\033[01;36m\]$PWD\[\033[00m\]\n\$ '
else
    PS1='${debian_chroot:+($debian_chroot)}\u@\h:\w\$ '
fi
unset color_prompt force_color_prompt

# If this is an xterm set the title to user@host:dir
case "$TERM" in
xterm*|rxvt*)
    PS1="\[\e]0;${debian_chroot:+($debian_chroot)}\u@\h: \w\a\]$PS1"
    ;;
*)
    ;;
esac

** Is there a directory history for bash?

• https://superuser.com/questions/299694/is-there-a-directory-history-for-bash

You can build your own cd command with pushd, popd, dirs , dirs -v builtin commands.

Usage

• cd -- ( list current history )

• cd -num ( go to num directory )

• cd - ( go to previous directory )

function cd () 
{ 
    local hnum=16;
    local new_dir index dir cnt;
    if ! [ $# -eq 0 ]; then
        if [[ $# -eq 2 && $1 = "--" ]]; then
            shift;
        else
            if ! { 
                [ $# -eq 1 ] && [[ $1 =~ ^(-[0-9]{,2}|-|--|[^-].*)$ ]]
            }; then
                builtin cd "$@";
                return;
            fi;
        fi;
    fi;
    [ "$1" = "--" ] && { 
        dirs -v;
        return
    };
    new_dir=${1:-$HOME};
    if [[ "$new_dir" =~ ^-[0-9]{,2}$ ]]; then
        index=${new_dir:1};
        if [ -z "$index" ]; then
            new_dir=$OLDPWD;
        else
            new_dir=$(dirs -l +$index) || return;
        fi;
    fi;
    pushd -- "$new_dir" > /dev/null || return;
    popd -n +$hnum &> /dev/null || true;
    new_dir=$PWD cnt=1;
    while dir=$(dirs -l +$cnt 2> /dev/null); do
        if [ "$dir" = "$new_dir" ]; then
            popd -n +$cnt > /dev/null;
            continue;
        fi;
        let cnt++;
    done
}