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shell [2019/01/14 12:21]
 shell [2024/01/16 21:35] (current)
rzr
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 +===== Shell (Command Line Interpreter) =====
 +
 +  * https://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#tag_18_05_02
 +  * Reference : http://www.gnu.org/software/bash/manual/html_node/Special-Parameters.html#Special-Parameters
 +  * http://www.blaess.fr/christophe/memo_programmation_shell.html
 +  * https://github.com/lmorg/murex# JsoN
 +
 +==== KSH ====
 +
 +  * korn : http://www.last.fm/user/nmental/journal/2007/09/30/a52jn_linux_humor_ed._2_%28korn_meets_korn%29
 +
 +
 +==== GNU TOOLS ====
 +
 +==== variables ====
 +
 +args :
 +  "$@"
 +
 +From shell :
 +  a=SHELL ; b=$(eval "echo \${${a}}" ); echo $b
 +  /bin/bash
 +
 +Same with makefiles :
 +  a=SHELL ; b=$$(eval "echo \$${$${a}}" ); echo $$b
 +
 +But it will fail if using gmake env
 +  a=CURDIR ; b=$$(eval "echo \$${$${a}}" ); echo $$b
 +
 +
 +   export ${USER}_KEY=${EMAIL}
 +   t=${USER}_KEY
 +   VAL=$(eval echo \${t} )
 +   echo $VAL
 +
 +   ps $(</var/run/exim4/exim.pid)
 +
 +
 +
 +==== COREUTILS ====
 +
 +  expr --version # expr (GNU coreutils) 8.13
 +  
 +  expr 0 + 1 && echo "ok as expected  [$?]" # 0
 +  expr 1 + 0 && echo "ok as expected  [$?]" # 0
 +  expr 0 + 0 || echo "ko unexpected [$?]" # 1
 +  
 +  expr 0 || echo "ko unexpected [$?]" # 1 
 +
 +http://www.gnu.org/software/coreutils/manual/coreutils.html#expr-invocation
 +
 +       Exit status is 0 if EXPRESSION is neither null nor 0, 1 if EXPRESSION is null or 0, 2 if EXPRESSION is syntactically invalid, and 3 if an error occurred.
 +
 +  echo "i="{1,2,3}
 +  i=1 i=2 i=3
 +
 +
 +@tag: WtF
 +
 +
 +
 +==== Escape ====
 +
 +  mkdir -p $(dirname "${mypath}") 
 +
 +will fail, use workaround :
 +
 +  dir=$(dirname "${mypath}") && mkdir -p "$dir"
 +
 +
 +==== Flow Control : ====
 +
 +if:
 +
 +  if ! true ; then echo then ; else echo else ; fi # print : else
 +
 +
 +    t=1 ; if [ "$t" != "0" ] && [ "$t" != "" ] ;  then echo "zero" ; fi
 +
 +for in :
 +
 +  export ARG=DllCanUnloadNow ; for f in *.lib  ;  do  echo "# $f:" ; dumpbin /symbols $f | grep $ARG ;  done
 +
 +for using seq (or w/ [[bash]] (1..255) ):
 +
 +  p=192.168.0 ; for i in $(seq 1 255) ; do ping -c 1  $p.$i > /dev/null 2>&1 && echo "$p.$i" ; done
 +
 +
 +for () :
 +  for (( i=0; $i <= 999 ; i++ )) ; do echo $i ; done
 +
 +
 +while : ( will eat one line each line)
 +
 +  cat $F | while l=`line` ; do  echo -E "$l" >> $F.tmp ; t=`line` ; done ; mv $F $F.orig ; mv $F.tmp $F
 +
 +
 +case :
 +
 +    case "$m" in
 +        jan | Jan)
 +            m=01; ;;
 +            
 +UntiL :
 +            
 +  until ping -w 1 -c 1 "$server" &>/dev/null ;do
 +    sleep 1
 +    n=$(( n+1 ))
 +    [ $n -eq 30 ] && break
 +  done
 +            
 +            
 +
 +<code>
 +#! /bin/bash
 +FILE=$1
 +# read $FILE using the file descriptors
 +exec 3<&0
 +exec 0<$FILE
 +while read line
 +do
 + # use $line variable to process line
 + echo $line
 +done
 +exec 0<&3
 +</code>
 +
 +
 +  * https://www.vidarholen.net/contents/blog/?p=1035
 +
 +==== eval ====
 +
 +<code>
 +    list='PWD USER'
 +    for key in ${list} ; do
 +        value=$(eval echo \$${key})
 +        echo "${key}=${value}"
 +    done
 +</code>
 +
 +
 +
 +===== Line =====
 +
 +  ls | awk '{ system ($0 ) }' 
 +
 +  ls | while L=`line`; do     echo $L;         read t ;     exit;     done; # will not work 
 +
 +
 +Line per line : use  IFS=$'\n'
 +
 +  * http://www.osxfaq.com/tips/unix-tricks/week98/thursday.ws
 +
 +<code>
 +prefix="date" ; IFS=$'\n' ; while [ 1 ] ; do date ; sleep 1 ; done | while read line ; do p="$(date +%Y%m%d%H%M%S)" &&  echo "$p: $prefix: $line" ; done
 +20131210122521: date: Tue Dec 10 12:25:21 CET 2013
 +20131210122522: date: Tue Dec 10 12:25:22 CET 2013
 +</code>
 +
 +
 +===== Pipe =====
 +
 +  ls /dontexist ; echo $? # = 2
 +  ls /dontexist | tee log ; echo $? # = 0
 +  ls /dontexist | tee log ; echo $PIPESTATUS # = 2
 +
 +
 +For Plain Sh or BusyBox
 +
 +<code>
 +
 +Workaound for '/bin/sh' or busybox
 +
 +status=0
 +eval ` { ls /dontexists || echo status="$?"; } | tee /dev/null`
 +echo "# status=${status}"
 +
 +Trace :
 +
 +busybox sh ~/bin/test.sh 
 ++ status=0
 ++ ls /dontexists
 ++ tee /dev/null
 +ls: /dontexists: No such file or directory
 ++ echo status=1
 ++ eval status=1
 ++ status=1
 ++ echo # status=1
 +# status=1
 +
 +
 +</code>
 +
 +  * https://superuser.com/questions/704460/how-do-you-use-pipestatus-tee-and-bin-sh-together/925140#925140
 +  * https://www.perkin.org.uk/posts/how-to-fix-stdio-buffering.html# BuffeR AwK
 +
 +@TaG: PipE
 +
 +
 +===== Multitask =====
 +
 +  #{
 +  test_()
 +  {
 +  while [ 1 ]
 +  do
 +  echo "$*=$$"
 +  sleep 1
 +  done
 +  }
 +
 +
 +  main_()
 +  {
 +  test_ 1 &
 +  test_ 2
 +  }
 +
 +
 +  $*
 +  #}
 +
 +  /tmp/t.sh main_
 +
 +
 +
 +
 +===== Text manipulation =====
 +
 +recurvive grep :
 +
 +  find ~/bin/ -type f  -exec grep -Hn  rzr {} \;
 +
 +search & replace :
 +
 +  sed -e "s/rzr/RzR/g" < filein.txt >| fileout.txt
 +  sed -e "s/rzr/RzR/g" -i fileinout.txt
 +
 +
 +pipes and `` :
 +
 +  #! /bin/sh
 +  #file://~/bin/killall.sh
 +  kill -9 `ps aux | grep $* | cut -b0-10`
 +
 +  killall.sh gdb
 +
 +variables on sh bash
 +
 +  VARNAME=value
 +  echo ${VARNAME}
 +  export VARNAME #
 +
 +variables on csh tcsh
 +  set VARNAME value
 +  echo $VARNAME
 +  setenv VARNAME value
 +
 +[[regex]] on Variables :
 +
 +  echo ${EMAIL}
 +  # root@localhost
 +  echo ${EMAIL/@/(a)}
 +  # root(a)localhost
 +
 +=== Variables===
 +
 +  $ echo $RM
 +  $ echo ${RM:=rm}
 +  rm
 +  $ echo $RM
 +  rm
 +  $ RM=delete.sh
 +  $ echo ${RM:=rm}
 +  delete.sh
 +  $ echo $RM
 +  delete.sh
 +==== stdout ====
 +
 +
 +  printf "%c\n" $'\x31' # 1
 +
 +  decimal=49
 +  eval printf \"%c\\n\" \$\'\\x$(printf "%02x" $decimal )\' # 1
 +
 +  eval printf \"%c\\n\" \$\'\\x$(echo "obase=16;$decimal" | bc)\' # 1
 +
 +
 +  tar cf - $(find . -iname "*.h")  | tar xvf - -C  ${DESTDIR}/include
 +
 +==== SED / [[AWK]] ====
 +
 +  find . -name "*,*" -type d -exec basename {} \; | awk '{ printf "mv " $1 " " ; sub (/_/,"-") ; print $1 }'
 +
 +  echo "9.999" | awk '{ printf "%.3f \n", $1 / 3 }'
 +
 +remove each file 
 +
 +  cat TODO | awk '{ system(" echo  " "rm -v \\\""  $1 "\\\" " ) }'
 +
 +
 +  * http://stackoverflow.com/questions/1429556/shell-bash-command-to-get-nth-line-of-stdout
 +
 +
 +head -50 | tail -1 = sed '50q;d' 
 +
 +@more: AwK SeD [[sh]]
 +==== USEFULL BLACK MAGIC COMMANDS ====
 +
 +Will rename [[C]] to [[C++]] files name conventions
 +
 +  # ls *.c | xargs -n 1 --replace echo "mv {} {}pp"
 +  mv mainc.c mainc.cpp
 +
 +  for i in *.ent; do mv $i ${i/ent/gml} ; done
 +
 +  rename 's/\.ent$/.gml/' *
 +
 +  man mmv
 +
 +  grep -v "^$" # remove empty lines
 +
 +prints executables :
 +  find . -perm +100  -type f -exec file {} \; | grep "ELF 32-bit LSB"  | cut -d':' -f 1 
 +
 +Copy all nodes :
 +
 +  s=/mnt/sdb6/
 +  d=/mnt/sdb2/
 +  cd "$s" && time tar cf - . | { cd "$d" && tar xfv - ; }
 +  
 +  cat files.txt | awk '{  print "tar cvf - " $0 " | tar xvf - -C /tmp "}' > /tmp/movefiles.sh
 +
 +
 +==== COOL OPTIONS ====
 +
 +  ifconfig | grep -A1 "^eth" #                                                                                                                            
 +  eth0      Link encap:Ethernet  HWaddr b8:70:??:??:??:??                                                                                                                                         
 +            UP BROADCAST MULTICAST  MTU:1500  Metric:1        
 +
 +==== SCRIPT SHELL ====
 +
 +A script shell is a simple series of shell commands :
 +see :
 +
 +# cat file.sh
 +  #! /bin/sh
 +  echo "I am a script shell"
 +  date
 +
 +# sh ./file.sh
 +  I am a script shell
 +  32 Dec 2000
 +
 +
 +
 +search / replace with sed in multiple files :
 +
 +  for fl in *.*; do
 +  mv $fl $fl.orig
 +  sed 's/FINDSTRING/REPLACESTRING/g' $fl.orig > "$fl"
 +  #rm -f $fl.orig
 +  done
 +
 +  sed -i 's/gif/png/g' *.wrl
 +
 +
 +How to substract : 09 - 1 to return 08
 +
 +  totem  mms://vipmms.canalplus.fr/canalplus/zapping_`expr  $(date +%y%m%d) - 1`_a.wmv
 +
 +
 +
 +==== PER HOST ENV ====
 +
 +
 +  cat ../chhome/env-chhome.sh
 +  #===/bin/sh===
 +  # echo "+ file://~/env-chhome.sh"
 +
 +  t=${HOME}/etc/home/$HOSTNAME/$USER
 +  # t=/home/$USER/etc/home/$HOSTNAME/$USER
 +  [[ -d $t ]] && HOME=$t && export HOME
 +
 +  # file://~/.profile     : ok:console+login+bash
 +  # file://~/.login       : ko:console+login+bash
 +  # file://~/.xsession    : on [[Debian]]
 +  # file://~/.xinitrc     :
 +
 +  # t=env-chhome.sh
 +  # [[ -f $t ]] && source $t
 +
 +  # echo "- file://~/env-chhome.sh"
 +
 +=== Joke ===
 +
 +  echo '[q]sa[ln0=aln256%Pln256/snlbx]sb3135071790101768542287578439snlbxq'|dc 
 +===== MISC =====
 +
 +  * http://rzr.online.fr/isbn/2841772772 # [[Livre]] :  http://www.amazon.fr/exec/obidos/ASIN/2841772772/rzr-21/#
 +  * http://directory.fsf.org/text/editors/lesspipe.sh.html
 +  * http://arstechnica.com/guides/other/msh.ars/2
 +  * http://linuxgazette.net/133/cherian.html # Bash
 +  * http://www.linuxjournal.com/article/6158
 +  * http://chris-lamb.co.uk/2008/01/24/can-you-get-cp-to-give-a-progress-bar-like-wget/
 +  * http://zsh.sourceforge.net/FAQ/zshfaq03.html# 3.24: What's wrong with cut and paste on my xterm?
 +  * http://www.ibm.com/developerworks/aix/library/au-badunixhabits.html # AwK vs GreP
 +  * https://github.com/pbrisbin/scripts# ScripT
 +  * http://www.unixmen.com/10-great-and-powerful-linux-commands-you-may-need-to-know/
 +  * http://felixcrux.com/blog/syntax-highlighting-cat# [[ZSh]]
 +  * http://datavu.blogspot.fr/2014/08/useful-unix-commands-for-exploring-data.html
 +
 +
 +===== TEXT =====
 +
 +Here is the way to reverse "od" output :
 +
 +
 +    echo "test" | od -A x -t x1 | sed -e 's|^[0-f]* ?||g' | xxd -r
 +    test
 +
 +
 +  * http://stackoverflow.com/questions/794902/whats-the-opposite-of-od1/25100021#25100021
 +
 +===== DATA FLOW =====
 +
 +   while read -n 1 byte ; do printf "%b" "$byte" ; done < "$input" > "$output" # BiN :
 +
 +  * http://unix.stackexchange.com/questions/10801/how-to-use-bash-script-to-read-binary-file-content
 +  * https://stackoverflow.com/questions/314675/how-to-redirect-output-of-an-entire-shell-script-within-the-script-itself#
 +
 +
 +
 +===== MISC =====
 +
 +  * https://github.com/BYVoid/Batsh# BaT BasH CompileR
 +  * http://ohmyz.sh/# ZsH
 +  * http://code.joejag.com/2014/why-zsh.html# ZsH
 +  * http://linuxfr.org/news/liquid-prompt-1-9# PrompT
 +  * http://www.shellcheck.net/about.html# AnalysiS
 +  * https://github.com/shellinabox/shellinabox# WeB
 +  * https://news.ycombinator.com/item?id=18898523# AliaS
 +  * https://github.com/zerobyte-id/SEcraper# SearcH
 +  * https://docs.microsoft.com/en-us/powershell/scripting/install/installing-powershell-core-on-linux?view=powershell-7.1# PowerShell
 +  * https://mhoffman.github.io/2015/05/21/how-to-navigate-directories-with-the-shell.html# ToDo
 +  * https://github.com/Nukesor/pueue# QueuE ToDo TesT
 +  * https://tratt.net/laurie/blog/2024/faster_shell_startup_with_shell_switching.html
 +
 +
 +===== MorE =====
 +
 +@TaG : [[RegEx]] [[Perl]] [[DOS]] [[Unix]] [[AWK]] [[sed]] [[awk]] [[bash]] [[javascript]] [[script]] PrograM ScripT
 +
 +{{http://www.helmsmusic.com/images/aug13_hell_station.jpg}}
 +
  
 
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