Author Archives: jeffrin

GNU coreutils: Sources of random data

script file contents #!/bin/bash get_seeded_random() { seed=”$1″ echo $seed openssl enc -aes-256-ctr -pass pass:”$seed” -nosalt \ /dev/null } shuf -i1-100 –random-source=<(get_seeded_random 45) using /dev/urandom $sudo shuf -i1-5 –random-source=/dev/urandom 1 2 4 3 5 $sudo shuf -i1-5 –random-source=/dev/urandom 3 4 5 1 2 $sudo shuf -i1-5 –random-source=/dev/urandom 4 5 2 1 3 $sudo shuf -i1-5 –random-source=/dev/urandom …

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What if a user or group name is a string of digits?

root>useradd 1991 root>mkdir /home/1991 root>chown 1991.1991 /home/1991/ root>passwd 1991 Enter new UNIX password: Retype new UNIX password: passwd: password updated successfully root>login 1991 Password: The programs included with the Debian GNU/Linux system are free software; the exact distribution terms for each program are described in the individual files in /usr/share/doc/*/copyright. Debian GNU/Linux comes with ABSOLUTELY …

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GNU coreutils: signal specifications . commands “kill” and “nohup”

$kill -l 1) SIGHUP 2) SIGINT 3) SIGQUIT 4) SIGILL 5) SIGTRAP 6) SIGABRT 7) SIGBUS 8) SIGFPE 9) SIGKILL 10) SIGUSR1 11) SIGSEGV 12) SIGUSR2 13) SIGPIPE 14) SIGALRM 15) SIGTERM 16) SIGSTKFLT 17) SIGCHLD 18) SIGCONT 19) SIGSTOP 20) SIGTSTP 21) SIGTTIN 22) SIGTTOU 23) SIGURG 24) SIGXCPU 25) SIGXFSZ 26) SIGVTALRM 27) …

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GNU coreutils: block size related to df command

ABOUT df df (abbreviation for disk free) is a standard Unix command used to display the amount of available disk space for file systems on which the invoking user has appropriate read access. df is typically implemented using the statfs or statvfs system calls. [bash] $df Filesystem 1K-blocks Used Available Use% Mounted on udev 1921644 …

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