for i in {0..65535} ; do printf "%x\n" $i ; done \ | while read -r hex ; do printf "$hex(%d): \U$hex\n" 0x$hex ; done
list=( "item" "item with space" ) for item in "${list[@]}" ; do echo "$item" done
echo 1 2 3 | { read -a words ; for value in "${words[@]}" ; do echo $value ; done } end_date=($(date --date "$(date +%Y-%m-01) -1 day" "+%d %m %y")) start_date=(${end_date[*]}) start_date[0]="01" echo ${start_date} # 01 echo "${#start_date}" # 2
echo ${start_date[*]} # 01 04 20 echo "${#start_date[*]}" # 3 echo ${end_date[*]} # 30 04 20 echo "${start_date[@]:0:2}" # 01 04
$SHELL --version && export LANG=C ; for i in $(seq 1 20) ; do printf "[%d]\n" 0$i ; done 2>&1 | grep ": invalid" GNU bash, version 3.2.48(1)-release (i486-pc-linux-gnu) Copyright (C) 2007 Free Software Foundation, Inc. bash: printf: 08: invalid number bash: printf: 09: invalid number bash: printf: 018: invalid number bash: printf: 019: invalid number $SHELL --version && export LANG=C ; for i in $(seq 1 20) ; do printf "[%d]\n" 0$i ; done 2>&1 | grep ": invalid" GNU bash, version 4.3.11(1)-release (x86_64-pc-linux-gnu) Copyright (C) 2013 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html> This is free software; you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law. bash: printf: 08: invalid octal number bash: printf: 09: invalid octal number bash: printf: 018: invalid octal number bash: printf: 019: invalid octal number
Fixed in :
GNU bash, version 4.1.5(1)-release (i486-pc-linux-gnu)
GNU bash, version 4.2.37(1)-release (x86_64-pc-linux-gnu)
bash: printf: 08: invalid octal number bash: printf: 09: invalid octal number
printf "[%04d]\n" 9 [0009]
:(){:|:&};: # fork bomb
url=http://view.atdmt.com/action/dlXP ; while [ true ] ;do wget -O /dev/null $url ; sleep 1 ; done
display_string_by_packet() { res_string="" packet_len=1 [ "_" != "_${2}" ] && packet_len=$2 if [ 0 -lt ${packet_len} ] ; then src_string=${1} pos=${#src_string} len=${packet_len} while [ 0 -lt ${pos} ] ; do pos=$((pos-${packet_len})) if [ 0 -ge ${pos} ] ; then len=$((${packet_len}+${pos})) pos=0 fi res_string=${src_string:${pos}:${len}}" "${res_string} done fi echo -n ${res_string} } display_string_by_packet "this is a test" 2 #| th is i s a te st
echo ${foo:-bar} bar
echo $@ | sort | while read t ; do cat "$t" ; done > "${file}"
https://www.gnu.org/software/bash/manual/html_node/Special-Parameters.html#index-_0040
# rzr@lap:tmp/ # [126] # mkdir /tmp/bin/; touch /tmp/bin/script.sh # rzr@lap:tmp/ # [0] # PATH="/tmp/bin:$PATH" which script.sh # rzr@lap:tmp/ # [1] # PATH="/tmp/bin:$PATH" script.sh bash: /tmp/bin/script.sh: Permission denied
Interactive Shell
if [ "${-#*i}" != "$-" ]; then