Linux Flashcards

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Answer 1

NAME ps -- process status SYNOPSIS ps [-AaCcEefhjlMmrSTvwXx] [-O fmt | -o fmt] [-G gid[,gid...]] [-g grp[,grp...]] [-u uid[,uid...]] [-p pid[,pid...]] [-t tty[,tty...]] [-U user[,user...]] ps [-L] DESCRIPTION The ps utility displays a header line, followed by lines containing information about all of your processes that have controlling terminals. A different set of processes can be selected for display by using any combination of the -a, -G, -g, -p, -T, -t, -U, and -u options. If more than one of these options are given, then ps will select all processes which are matched by at least one of the given options. For the processes which have been selected for display, ps will usually display one line per process. The -M option may result in multiple output lines (one line per thread) for some processes. By default all of these output lines are sorted first by controlling terminal, then by process ID. The -m, -r, and -v options will change the sort order. If more than one sorting option was given, then the selected processes will be sorted by the last sorting option which was specified. For the processes which have been selected for display, the information to display is selected based on a set of keywords (see the -L, -O, and -o options). The default output format includes, for each process, the process' ID, controlling terminal, CPU time (including both user and system time), state, and associated command.

Answer 2

NAME kill -- terminate or signal a process ``` SYNOPSIS kill [-s signal_name] pid ... kill -l [exit_status] kill -signal_name pid ... kill -signal_number pid ... ``` DESCRIPTION The kill utility sends a signal to the processes specified by the pid operand(s). Only the super-user may send signals to other users' processes.

Answer 3

NAME pgrep, pkill -- find or signal processes by name SYNOPSIS pgrep [-Lafilnoqvx] [-F pidfile] [-G gid] [-P ppid] [-U uid] [-d delim] [-g pgrp] [-t tty] [-u euid] pattern ... pkill [-signal] [-ILafilnovx] [-F pidfile] [-G gid] [-P ppid] [-U uid] [-g pgrp] [-t tty] [-u euid] pattern ... DESCRIPTION The pgrep command searches the process table on the running system and prints the process IDs of all processes that match the criteria given on the command line. The pkill command searches the process table on the running system and signals all processes that match the criteria given on the command line.

Answer 4

NAME top - display and update sorted information about processes ``` SYNOPSIS top [-a | -d | -e | -c ] [-F | -f] [-h] [-i ] [-l ] [-ncols ] [-o ] [-O ] [-R | -r] [-S] [-s ] [-n ] [-stats ] [-pid ] [-user ] [-U ] [-u] ``` DESCRIPTION The top program periodically displays a sorted list of system processes. The default sorting key is pid, but other keys can be used instead. Various output options are avail- able.

Answer 5

NAME ssh -- OpenSSH SSH client (remote login program) SYNOPSIS ssh [-1246AaCfgKkMNnqsTtVvXxYy] [-b bind_address] [-c cipher_spec] [-D [bind_address:]port] [-e escape_char] [-F configfile] [-I pkcs11] [-i identity_file] [-L [bind_address:]port:host:hostport] [-l login_name] [-m mac_spec] [-O ctl_cmd] [-o option] [-p port] [-R [bind_address:]port:host:hostport] [-S ctl_path] [-W host:port] [-w local_tun[:remote_tun]] [user@]hostname [command] ``` DESCRIPTION ssh (SSH client) is a program for logging into a remote machine and for executing commands on a remote machine. It is intended to replace rlogin and rsh, and provide secure encrypted communications between two untrusted hosts over an insecure network. X11 connections and arbitrary TCP ports can also be forwarded over the secure channel. ``` ssh connects and logs into the specified hostname (with optional username). The user must prove his/her identity to the remote machine using one of several methods depending on the protocol version used (see below). If command is specified, it is executed on the remote host instead of a login shell.

Answer 6

NAME link, ln -- make links SYNOPSIS ln [-Ffhinsv] source_file [target_file] ln [-Ffhinsv] source_file ... target_dir link source_file target_file DESCRIPTION The ln utility creates a new directory entry (linked file) which has the same modes as the original file. It is useful for maintaining multiple copies of a file in many places at once without using up storage for the copies; instead, a link points to the original copy. There are two types of links; hard links and symbolic links. How a link points to a file is one of the differences between a hard and symbolic link.

Answer 7

NAME launchd -- System wide and per-user daemon/agent manager SYNOPSIS launchd [-d] [-D] [-s] [-S SessionType] [-- command [args ...]] DESCRIPTION launchd manages processes, both for the system as a whole and for individual users. The primary and preferred interface to launchd is via the launchctl(1) tool which (among other options) allows the user or administrator to load and unload jobs. Where possible, it is preferable for jobs to launch on demand based on criteria specified in their respective configuration files. During boot launchd is invoked by the kernel to run as the first process on the sys-tem and to further bootstrap the rest of the system. You cannot invoke launchd directly. ENVIRONMENTAL VARIABLES LAUNCHD_SOCKET This variable is exported when invoking a command via the launchd command line. It informs launchctl how to find the correct launchd to talk to.

Answer 8

NAME launchctl -- Interfaces with launchd SYNOPSIS launchctl [subcommand [arguments ...]] DESCRIPTION launchctl interfaces with launchd to load, unload daemons/agents and generally control launchd. launchctl supports taking subcommands on the command line, interactively or even redirected from standard input. These commands can be stored in $HOME/.launchd.conf or /etc/launchd.conf to be read at the time launchd starts.

Answer 9

Example: $alias rtest='bundle exec rake test'

Linux Flashcards

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