meta data for this page
  •  

Különbségek

A kiválasztott változat és az aktuális verzió közötti különbségek a következők.

Összehasonlító nézet linkje

Előző változat mindkét oldalonElőző változat
Következő változat		Előző változat
linux [2019/04/16 11:28] – adminlinux [2024/03/12 16:57] (aktuális) – admin
Sor 1: Sor 1:
 ===== Linux okosságok ===== ===== Linux okosságok =====
 +
 +==== Dátum figyelés ====
 +
 +  function date_diff()
 +  {
 +    date='2020-08-12T16:00:10'
 +    epoch=$(date -d "$date" +%s)
 +    if [ "$epoch" -lt "$(date -d '1 minute ago' +%s)" ] ; then
 +  #[[ "$(date -d '2024-02-01 17:26:00' +%s)" -lt "$(date +%s)" ]] && echo elmult || echo nem
 +        echo At least 3 days ago
 +    else
 +        echo Too recent
 +    fi
 +  }
 +
 +
 +==== Reboot, ha nem megy a szabályos reboot ====
 +
 +  # echo s > /proc/sysrq-trigger
 +  # echo u > /proc/sysrq-trigger
 +  # echo s > /proc/sysrq-trigger
 +  # echo b > /proc/sysrq-trigger
 +
 +This requests the kernel to do:
 +
 +emergency sync of the block devices; 
 +mount readonly of all filesystems; 
 +again a sync; 
 +force an immediate boot; (you can also use o for poweroff)
 +
 +==== dm-* device-ok felderítése ====
 +
 +  find /dev/ -name "dm-*" -exec readlink -n {} \; -exec echo " -->" {} \;
 +==== SCSI (re)scan ====
 +
 +  #!/bin/sh
 +  for I in `ls -d /sys/class/scsi_device/*`; do
 +        echo ${I}
 +        echo "1" > ${I}/device/rescan
 +  done
 +
 +  #!/bin/sh
 +  for I in `ls -d /sys/class/scsi_host/host*`; do
 +        echo ${I}
 +        echo "- - -" > ${I}/scan
 +  done
 +
 +
 +==== Yum-mal telepített csomagok listázása log fájlból ====
 +
 +  cat /var/log/yum.log | sed "s#.\+: \?\(.\+\)#\1#" | sort
 +==== Disk perf. teszt DD-vel ====
 +
 +<file>
 +#!/bin/bash
 +echo -n "Fajl nev: "
 +read FNEV
 +echo -n "Blokk meret (Byte): "
 +read BS
 +echo -n "Fajl meret (MByte): "
 +read FS
 +COUNT=$((FS*1024*1024 / $BS))
 +COUNT=$(echo $COUNT | sed 's/\..*$/g/')
 +echo -n "Diszk irasa (dd if=/dev/zero of=$FNEV bs=$BS count=$COUNT)… "
 +SEC=$(timex dd if=/dev/zero of=$FNEV bs=$BS count=$COUNT 2>&1 | awk '/real/{print $2}' | awk -F'.' '{print $1}')
 +echo "$(($FS / $SEC)) MB/s"
 +</file>
  
 ==== BOOT probléma ==== ==== BOOT probléma ====
Sor 5: Sor 72:
 GRUB menüben a "quiet" paraméter helyére "dracut rdshell"-t betenni GRUB menüben a "quiet" paraméter helyére "dracut rdshell"-t betenni
  
 +==== ~/.vimrc ====
 +
 +  set number background=dark
 +  syntax on
 +  highlight Comment    ctermfg=119
 +  highlight Identifier ctermfg=99AA00
 +  set ts=4 sw=4
 +  undolevels=1000
 ==== RAID megoldások ==== ==== RAID megoldások ====
  
Sor 27: Sor 102:
   lvcreate -s -L 1G -n blabla /dev/vg/blablalv   lvcreate -s -L 1G -n blabla /dev/vg/blablalv
   lvdisplay -C -S lv_role=snapshot   lvdisplay -C -S lv_role=snapshot
 +
 +==== sudo jog másik userhez ====
 +
 +  non-root-user ALL = (appuser) NOPASSWD: ALL
 +
  
 ==== NMON adatgyűjtés ==== ==== NMON adatgyűjtés ====
Sor 49: Sor 129:
 </file> </file>
  
-==== Ismétlődő sorok számolása ====+==== Email címek extraktálása AIX alatt ====
  
-  cat file | sed 's/([^(]*)$/,&/' | awk -F'[,]' '{a[$2]++}END{for(k in a) print $1,k,$3,"("a[k]"x)"}'+  perl -wne'while(/[\w\.\-]+@[\w\.\-]+\w+/g){print "$&\n"}'
  
-==== /dev/stdin üres-e? (Van-e adat a pipe-ban?) ==== 
- 
-  [ ! -t 0 ] 
- 
-==== Bekezdésre greppelés Linux alatt (AIX: grep -p) ==== 
- 
-  awk 'BEGIN{RS=ORS="\n\n";FS=OFS="\n"}/Storage Slots/ 
- 
-==== Bash színkódok törlése szövegből ==== 
- 
-  sed "s,\x1B\[[0-9;]*[a-zA-Z],,g" 
 ==== Hiányzik az "add-apt-repository": ==== ==== Hiányzik az "add-apt-repository": ====
  
Sor 100: Sor 169:
 # Get current swap usage for all running processes # Get current swap usage for all running processes
 # Erik Ljungstrom 27/05/2011 # Erik Ljungstrom 27/05/2011
 +echo "Swappiness: $(cat /proc/sys/vm/swappiness)"
 SUM=0 SUM=0
 OVERALL=0 OVERALL=0
Sor 116: Sor 186:
 </file> </file>
  
-==== Sztringek hexa értelmezésének kiküszöbölése ==== 
- 
-Pl: 
-  $((10#`date +%H`)) 
- 
-==== A grep "-o" kapcsolójának kiváltása perl-lel ==== 
- 
-  perl -lne '/reguláris kifejezés/ && print $&' 
 ==== Törölt fájlok, amik nem szabadították még fel a helyet ==== ==== Törölt fájlok, amik nem szabadították még fel a helyet ====
   lsof |(sed 1q; grep deleted)   lsof |(sed 1q; grep deleted)
-==== BASH változó manipulációk ==== +    
- +
-^Syntax^Meaning^ +
-|${#var} | String length (number of characters in $var).| +
-|${var%%^^%%} | Uppercase alphanumeric characters in $var.| +
-|${parameter?err_msg},${parameter:?err_msg} | If parameter set, use it, else print err_msg and abort the script with an exit status of 1. Both forms nearly equivalent. The : makes a difference only when parameter has been declared and is null.| +
-|${parameter-default},${parameter:-default} | If parameter not set, use default. ${parameter-default} and ${parameter:-default} are almost equivalent. The extra : makes a difference only when parameter has been declared, but is null.| +
-|${parameter=default},${parameter:=default} | If parameter not set, set it to default. Both forms nearly equivalent. The : makes a difference only when $parameter has been declared and is null.| +
-|${parameter+alt_value},${parameter:+alt_value} | If parameter set, use alt_value, else use null string. Both forms nearly equivalent. The : makes a difference only when parameter has been declared and is null.| +
-|${var#Pattern} | Remove from $var the shortest part of $Pattern that matches the front end of $var.| +
-|${var##Pattern} | Remove from $var the longest part of $Pattern that matches the front end of $var.| +
-|${var%Pattern} | Remove from $var the shortest part of $Pattern that matches the back end of $var.| +
-|${var%%%%Pattern} | Remove from $var the longest part of $Pattern that matches the back end of $var.| +
-|${var:pos} | Variable var expanded, starting from offset pos.| +
-|${var:pos:len} | Expansion to a max of len characters of variable var, from offset pos.| +
-|${var/Pattern/Replacement} | First match of Pattern, within var replaced with Replacement. If Replacement is omitted, then the first match of Pattern is replaced by nothing, that is, deleted.| +
-|${var%%//%%Pattern/Replacement} | Global replacement. All matches of Pattern, within var replaced with Replacement. If Replacement is omitted, then all occurrences of Pattern are replaced by nothing, that is, deleted.| +
-|${var/#Pattern/Replacement} | If prefix of var matches Pattern, then substitute Replacement for Pattern.| +
-|${var/%Pattern/Replacement} | If suffix of var matches Pattern, then substitute Replacement for Pattern.| +
-|${!varprefix*},${!varprefix@} | Matches names of all previously declared variables beginning with varprefix.| +
- +
-forrás: [[http://tldp.org/LDP/abs/html/parameter-substitution.html]] +
- +
-==== Gyakori BASH RC kódok ==== +
- +
-^Exit Code Number ^Meaning ^Example ^Comments^ +
-|1 |Catchall for general errors |let "var1 = 1/0" |Miscellaneous errors, such as "divide by zero" and other impermissible operations| +
-|2 |Misuse of shell builtins (according to Bash documentation) |empty_function() {} |Missing keyword or command| +
-|126 |Command invoked cannot execute |/dev/null |Permission problem or command is not an executable| +
-|127 |"command not found" |illegal_command |Possible problem with $PATH or a typo| +
-|128 |Invalid argument to exit |exit 3.14159 |exit takes only integer args in the range 0 - 255 (see first footnote)| +
-|128+n |Fatal error signal "n" |kill -9 $PPID of script |$? returns 137 (128 + 9)| +
-|130 |Script terminated by Control-C |Ctl-C |Control-C is fatal error signal 2, (130 = 128 + 2, see above)| +
-|255* |Exit status out of range |exit -1 |exit takes only integer args in the range 0 - 255| +
- +
-==== Hiba csatorna színezése ==== +
- +
-   $ parancs 2> >(while read line; do echo -e "\e[01;31m$line\e[0m"; done) +
-    +
-==== Terminál kurzor pozícionálás ==== +
-   +
-- Position the Cursor: +
-  \033[<L>;<C>H +
-     Or +
-  \033[<L>;<C>f +
-  puts the cursor at line L and column C. +
-- Move the cursor up N lines: +
-  \033[<N>A +
-- Move the cursor down N lines: +
-  \033[<N>B +
-- Move the cursor forward N columns: +
-  \033[<N>C +
-- Move the cursor backward N columns: +
-  \033[<N>D +
- +
-- Clear the screen, move to (0,0): +
-  \033[2J +
-- Erase to end of line: +
-  \033[K +
- +
-- Save cursor position: +
-  \033[s +
-- Restore cursor position: +
-  \033[u +
- +
-==== "Homokóra" - progress icon ==== +
-v1: +
-<file> +
-a=1 +
-sp="/-\|" +
-echo -n ' ' +
-while true +
-do +
-    printf "\b${sp:a++%${#sp}:1}" +
-done +
-</file> +
-v2: +
-<file> +
-spinner() +
-{ +
-    local pid=$1 +
-    local delay=0.75 +
-    local spinstr='|/-\' +
-    while [ "$(ps a | awk '{print $1}' | grep $pid)" ]; do +
-        local temp=${spinstr#?} +
-        printf " [%c]  " "$spinstr" +
-        local spinstr=$temp${spinstr%"$temp"} +
-        sleep $delay +
-        printf "\b\b\b\b\b\b" +
-    done +
-    printf "    \b\b\b\b" +
-} +
-</file>+
 ==== Hosszú processz végeztéről értesítő email ==== ==== Hosszú processz végeztéről értesítő email ====
  
Sor 229: Sor 199:
 done done
 echo Lefutott | mail -s "Process $1 lefutott (${hostname})" $MAILTO echo Lefutott | mail -s "Process $1 lefutott (${hostname})" $MAILTO
 +</file>
 +
 +==== processz elrejtése a PS kimenetből ====
 +
 +
 +<file>
 +/* https://unix.stackexchange.com/a/403918/119298
 + * capture calls to a routine and replace with your code
 + * gcc -Wall -O2 -fpic -shared -ldl -o shim_main.so shim_main.c
 + * LD_PRELOAD=/.../shim_main.so theprogram theargs...
 + */
 +#define _GNU_SOURCE /* needed to get RTLD_NEXT defined in dlfcn.h */
 +#include <stdlib.h>
 +#include <stdio.h>
 +#include <string.h>
 +#include <signal.h>
 +#include <unistd.h>
 +#include <dlfcn.h>
 +
 +typedef int (*pfi)(int, char **, char **);
 +static pfi real_main;
 +
 +/* copy argv to new location */
 +char **copyargs(int argc, char** argv){
 +    char **newargv = malloc((argc+1)*sizeof(*argv));
 +    char *from,*to;
 +    int i,len;
 +
 +    for(i = 0; i<argc; i++){
 +        from = argv[i];
 +        len = strlen(from)+1;
 +        to = malloc(len);
 +        memcpy(to,from,len);
 +        memset(from,'\0',len);    /* zap old argv space */
 +        newargv[i] = to;
 +        argv[i] = 0;
 +    }
 +    newargv[argc] = 0;
 +    return newargv;
 +}
 +
 +static int mymain(int argc, char** argv, char** env) {
 +    fprintf(stderr, "main argc %d\n", argc);
 +    return real_main(argc, copyargs(argc,argv), env);
 +}
 +
 +int __libc_start_main(pfi main, int argc,
 +                      char **ubp_av, void (*init) (void),
 +                      void (*fini)(void),
 +                      void (*rtld_fini)(void), void (*stack_end)){
 +    static int (*real___libc_start_main)() = NULL;
 +
 +    if (!real___libc_start_main) {
 +        char *error;
 +        real___libc_start_main = dlsym(RTLD_NEXT, "__libc_start_main");
 +        if ((error = dlerror()) != NULL) {
 +            fprintf(stderr, "%s\n", error);
 +            exit(1);
 +        }
 +    }
 +    real_main = main;
 +    return real___libc_start_main(mymain, argc, ubp_av, init, fini,
 +            rtld_fini, stack_end);
 +}
 </file> </file>
  
Sor 242: Sor 276:
   * [[http://www.howtogeek.com/howto/ubuntu/keyboard-shortcuts-for-bash-command-shell-for-ubuntu-debian-suse-redhat-linux-etc/|Keyboard Shortcuts for Bash]]   * [[http://www.howtogeek.com/howto/ubuntu/keyboard-shortcuts-for-bash-command-shell-for-ubuntu-debian-suse-redhat-linux-etc/|Keyboard Shortcuts for Bash]]
   * [[https://github.com/gdbtek/linux-cookbooks/blob/master/libraries/util.bash|Bash util functions]]   * [[https://github.com/gdbtek/linux-cookbooks/blob/master/libraries/util.bash|Bash util functions]]
 +  * [[https://ef.gy/forwarding-ipv4-to-ipv6|Forwarding IPv4 Ports to IPv6-only Hosts]]
 +  * [[https://www.techrepublic.com/article/how-to-setup-two-factor-authentication-in-linux|Két faktoros authentikáció linuxon]]
 +  * [[https://access.redhat.com/articles/17054|How do I find the FC ID (WWN) of a scsi device/LUN on Red Hat Enterprise Linux?]]