{"pages":[{"id":1797,"name":"apt-transport-https","one_liner":"Allows APT to fetch package repositories over encrypted HTTPS connections.","card":"# Use custom CA certificate for a specific repository\nAcquire::https::myrepo.example.com::CAInfo \"/etc/apt/certs/repo-ca.pem\";\n# Disable peer verification (NOT RECOMMENDED, TESTING ONLY)\nAcquire::https::myrepo.example.com::Verify-Peer \"false\";\n# Disable hostname verification for a specific host\nAcquire::https::myrepo.example.com::Verify-Host \"false\";\n# Define a Certificate Revocation List (CRL)\nAcquire::https::myrepo.example.com::CRLFile \"/etc/apt/certs/repo.crl\";","section":"1","section_name":"User Commands","categories":["networking","security","packaging"],"use_frequency":5,"package":"apt"},{"id":5992,"name":"curl","one_liner":"A versatile command-line tool for transferring data to or from servers via URLs.","card":"# Fetch content and display in terminal\ncurl https://example.com\n# Save remote file to local disk\ncurl -O https://example.com/file.zip\n# Send a POST request with JSON data\ncurl -X POST -H \"Content-Type: application/json\" -d '{\"key\":\"val\"}' https://api.site.com\n# Send form data\ncurl -F \"file=@photo.jpg\" https://upload.site.com\n# Follow redirects\ncurl -L https://shorturl.com\n# Include HTTP response headers\ncurl -I https://google.com","section":"1","section_name":"User Commands","categories":["networking","web"],"use_frequency":5,"package":"curl"},{"id":7279,"name":"dig","one_liner":"A flexible command-line utility for querying and troubleshooting DNS name servers.","card":"# Basic A record lookup: dig google.com\n# Get MX records for a domain: dig google.com MX\n# Query a specific DNS server: dig @8.8.8.8 google.com\n# Perform a reverse DNS lookup: dig -x 8.8.8.8\n# Get only the answer section: dig +short google.com\n# Trace the full delegation path: dig +trace google.com\n# Request a full zone transfer: dig axfr example.com @ns1.example.com","section":"1","section_name":"User Commands","categories":["networking","dns"],"use_frequency":5,"package":"bind9-dnsutils"},{"id":25237,"name":"ping","one_liner":"Check network connectivity by sending ICMP ECHO_REQUEST packets to a remote host.","card":"# Send 5 packets to a host\nping -c 5 google.com\n# Ping with a custom interval of 0.2 seconds\nping -i 0.2 192.168.1.1\n# Flood ping (root only) for rapid connectivity testing\nsudo ping -f 127.0.0.1\n# Send packets with a specific size (e.g., 1000 bytes)\nping -s 1000 google.com\n# Quiet mode, showing only summary statistics\nping -q -c 10 google.com\n# Numeric output only (no DNS lookup)\nping -n 8.8.8.8","section":"1","section_name":"User Commands","categories":["networking"],"use_frequency":5,"package":"inetutils-ping"},{"id":29275,"name":"rsync","one_liner":"A fast, versatile tool for syncing files locally or over a network.","card":"# Archive and sync folder contents (-a: archive, -v: verbose, -z: compress, -P: progress)\nrsync -avzP source_dir/ destination_dir/\n# Dry run to see what would happen without making changes\nrsync -av --dry-run source_dir/ user@host:/path/to/dest/\n# Delete files in destination that no longer exist in source\nrsync -av --delete source_dir/ destination_dir/\n# Exclude specific files or patterns\nrsync -av --exclude '*.log' source/ dest/\n# Transfer over SSH\nrsync -av -e ssh user@host:/remote/path /local/path","section":"1","section_name":"User Commands","categories":["networking","filesystem","backup"],"use_frequency":5,"package":"rsync"},{"id":21542,"name":"nc","one_liner":"Versatile network utility for reading/writing data across TCP, UDP, and Unix-domain sockets.","card":"# Connect to a port\nnc example.com 80\n# Listen for incoming connections\nnc -l 1234\n# Scan a range of ports\nnc -zv 192.168.1.1 20-80\n# Transfer a file\nnc -l 1234 > file.out # Receiver\nnc host 1234 < file.in # Sender\n# Simple chat server\nnc -lk 1234\n# Test UDP port\nnc -uvz 127.0.0.1 53\n# Act as a TCP proxy\nnc -l 1234 | nc example.com 80","section":"1","section_name":"User Commands","categories":["networking"],"use_frequency":5,"package":"netcat-openbsd"},{"id":21538,"name":"nc","one_liner":"Versatile network utility for reading/writing data across TCP, UDP, or Unix sockets.","card":"# Connect to a remote host/port\nnc google.com 80\n# Start a listener on a port\nnc -l 8080\n# Scan a range of ports on a host\nnc -zv 192.168.1.1 20-80\n# Send a file\nnc -l 1234 > output.txt (on receiver) | nc localhost 1234 < input.txt (on sender)\n# Perform a simple HTTP request\necho -e 'GET / HTTP/1.0\\r\\n\\r\\n' | nc google.com 80\n# Use as a TCP proxy\nnc -l 8080 | nc google.com 80","section":"1","section_name":"User Commands","categories":["networking"],"use_frequency":5,"package":"netcat-openbsd"},{"id":30004,"name":"scp","one_liner":"Securely copy files and directories between remote hosts using SSH.","card":"# Copy file to remote host\nscp localfile.txt user@host:/path/to/dest/\n# Copy directory to remote host\nscp -r ./mydir user@host:/remote/path/\n# Copy file from remote host\nscp user@host:/path/to/file.txt ./localdir/\n# Copy with specific private key\nscp -i ~/.ssh/id_rsa file.txt user@host:~\n# Copy using a custom port\nscp -P 2222 file.txt user@host:/path/\n# Limit bandwidth to 1000 Kbit/s\nscp -l 1000 largefile.iso user@host:/tmp/","section":"1","section_name":"User Commands","categories":["networking","filesystem"],"use_frequency":5,"package":"openssh-client-ssh1"},{"id":101856,"name":"sockaddr, sockaddr_storage, sockaddr_in, sockaddr_in6, sockaddr_un, socklen_t, in_addr, in6_addr, in_addr_t, in_port_t,","one_liner":"Data structures used for socket addressing in networking and IPC communications.","card":"# IPv4 structure assignment\nstruct sockaddr_in addr; addr.sin_family = AF_INET; addr.sin_port = htons(8080); addr.sin_addr.s_addr = INADDR_ANY;\n# Generic casting to sockaddr for bind/connect\nbind(sockfd, (struct sockaddr *)&addr, sizeof(addr));\n# IPv6 structure assignment\nstruct sockaddr_in6 addr6; addr6.sin6_family = AF_INET6; addr6.sin6_port = htons(8080); inet_pton(AF_INET6, \"::1\", &addr6.sin6_addr);\n# UNIX domain setup\nstruct sockaddr_un un; un.sun_family = AF_UNIX; strcpy(un.sun_path, \"/tmp/sock\");","section":"3","section_name":"Library Functions","categories":["networking","development","ipc"],"use_frequency":5,"package":"manpages-dev"},{"id":30003,"name":"scp","one_liner":"Securely copy files and directories between local and remote systems over SSH.","card":"# Copy file to remote server\nscp file.txt user@host:/path/to/dest/\n# Copy directory to remote server\nscp -r folder/ user@host:/path/to/dest/\n# Copy file from remote server\nscp user@host:/path/to/file.txt ./local/path/\n# Copy file from remote to remote (via local)\nscp -3 user1@host1:/file.txt user2@host2:/path/\n# Copy with specific SSH key and port\nscp -i ~/.ssh/id_rsa -P 2222 file.txt user@host:~\n# Copy with compression enabled\nscp -C large_file.iso user@host:~/backups/","section":"1","section_name":"User Commands","categories":["networking","filesystem"],"use_frequency":5,"package":"openssh-client"},{"id":101859,"name":"sockaddr, sockaddr_storage, sockaddr_in, sockaddr_in6, sockaddr_un, socklen_t, in_addr, in6_addr, in_addr_t, in_port_t,","one_liner":"Standardized structures for representing socket addresses across different network protocols.","card":"# IPv4 setup\nstruct sockaddr_in addr; addr.sin_family = AF_INET; addr.sin_port = htons(8080); addr.sin_addr.s_addr = INADDR_ANY;\n# IPv6 setup\nstruct sockaddr_in6 addr6; addr6.sin6_family = AF_INET6; addr6.sin6_port = htons(8080); inet_pton(AF_INET6, \"::1\", &addr6.sin6_addr);\n# Unix domain\nstruct sockaddr_un un; un.sun_family = AF_UNIX; strcpy(un.sun_path, \"/tmp/socket\");\n# Universal storage\nstruct sockaddr_storage ss; connect(fd, (struct sockaddr *)&ss, sizeof(ss));","section":"3","section_name":"Library Functions","categories":["networking","development","ipc"],"use_frequency":5,"package":"manpages-dev"},{"id":31794,"name":"ssh","one_liner":"Secure remote login client for executing commands and managing remote systems.","card":"# Connect to a remote host\nssh user@hostname\n# Run a single command remotely and exit\nssh user@hostname 'df -h'\n# Enable X11 forwarding\nssh -X user@hostname\n# Create a local SOCKS proxy for browsing\nssh -D 8080 user@hostname\n# Local port forwarding\nssh -L 9000:localhost:3000 user@hostname\n# Use a specific identity file\nssh -i ~/.ssh/id_ed25519 user@hostname\n# Jump through a proxy host\nssh -J user@proxy-host user@target-host","section":"1","section_name":"User Commands","categories":["networking","security","terminal"],"use_frequency":5,"package":"openssh-client"},{"id":44848,"name":"CURLOPT_URL","one_liner":"Sets the target URL for a libcurl network transfer.","card":"CURLcode curl_easy_setopt(CURL *handle, CURLOPT_URL, char *URL); # Set the destination URL; curl_easy_setopt(curl, CURLOPT_URL, \"https://example.com\"); # Perform the request; curl_easy_perform(curl); # URL must be null-terminated; ensure it is properly encoded per RFC 3986. # If no scheme is provided, libcurl defaults to HTTP or guesses by domain name.","section":"3","section_name":"Library Functions","categories":["networking","development","web"],"use_frequency":5,"package":"libcurl4-doc"},{"id":37290,"name":"yt-dlp","one_liner":"A powerful command-line tool to download video and audio from thousands of websites.","card":"# Download best quality video/audio as mp4\nyt-dlp -f \"bestvideo[ext=mp4]+bestaudio[ext=m4a]/best[ext=mp4]/best\" URL\n# Extract audio only\nyt-dlp -x --audio-format mp3 URL\n# Download a full playlist\nyt-dlp -i --yes-playlist URL\n# Download video with subtitles\nyt-dlp --write-auto-sub --sub-lang en URL\n# Restrict speed to avoid bandwidth hogging\nyt-dlp --limit-rate 2M URL\n# Download and save with specific filename template\nyt-dlp -o \"%(title)s.%(ext)s\" URL","section":"1","section_name":"User Commands","categories":["networking","web"],"use_frequency":5,"package":"yt-dlp"},{"id":31795,"name":"ssh","one_liner":"Secure shell client for remote login and command execution over untrusted networks.","card":"# Connect to remote host\nssh user@hostname\n# Specify identity file\nssh -i ~/.ssh/id_rsa user@hostname\n# Local port forwarding\nssh -L 8080:localhost:80 user@hostname\n# Dynamic SOCKS proxy\nssh -D 9090 user@hostname\n# Execute command remotely\nssh user@hostname 'ls -l /tmp'\n# Jump host to reach internal server\nssh -J jumpbox internal-host\n# Enable X11 forwarding\nssh -X user@hostname","section":"1","section_name":"User Commands","categories":["networking","security"],"use_frequency":5,"package":"openssh-client-ssh1"},{"id":120214,"name":"sockaddr, sockaddr_storage, sockaddr_in, sockaddr_in6, sockaddr_un, socklen_t, in_addr, in6_addr, in_addr_t, in_port_t,","one_liner":"Standard structures for defining and manipulating socket addresses across different network families.","card":"# IPv4 binding pattern\nstruct sockaddr_in addr = { .sin_family = AF_INET, .sin_port = htons(8080) };\ninet_pton(AF_INET, \"127.0.0.1\", &addr.sin_addr);\n# IPv6 binding pattern\nstruct sockaddr_in6 addr6 = { .sin6_family = AF_INET6, .sin6_port = htons(8080) };\ninet_pton(AF_INET6, \"::1\", &addr6.sin6_addr);\n# Unix domain path\nstruct sockaddr_un sun = { .sun_family = AF_UNIX };\nstrcpy(sun.sun_path, \"/tmp/socket\");\n# Universal storage\nstruct sockaddr_storage ss; socklen_t len = sizeof(ss);","section":"3","section_name":"Library Functions","categories":["networking","development","ipc"],"use_frequency":5,"package":"manpages-dev"},{"id":116959,"name":"sockaddr, sockaddr_storage, sockaddr_in, sockaddr_in6, sockaddr_un, socklen_t, in_addr, in6_addr, in_addr_t, in_port_t,","one_liner":"Standardized structures for representing and passing socket address information to networking system calls.","card":"# IPv4 setup: struct sockaddr_in addr; addr.sin_family = AF_INET; addr.sin_port = htons(8080); addr.sin_addr.s_addr = INADDR_ANY;\n# IPv6 setup: struct sockaddr_in6 addr; addr.sin6_family = AF_INET6; inet_pton(AF_INET6, \"::1\", &addr.sin6_addr);\n# UNIX setup: struct sockaddr_un addr; addr.sun_family = AF_UNIX; strcpy(addr.sun_path, \"/tmp/sock\");\n# Universal casting: bind(fd, (struct sockaddr *)&addr, sizeof(addr));\n# Handle varying sizes: struct sockaddr_storage ss; socklen_t len = sizeof(ss);","section":"3","section_name":"Library Functions","categories":["networking","development","ipc"],"use_frequency":5,"package":"manpages-dev"},{"id":101857,"name":"sockaddr, sockaddr_storage, sockaddr_in, sockaddr_in6, sockaddr_un, socklen_t, in_addr, in6_addr, in_addr_t, in_port_t,","one_liner":"Standard structures for defining socket addresses across IPv4, IPv6, and Unix domains.","card":"struct sockaddr_in sa; sa.sin_family = AF_INET; sa.sin_port = htons(8080); sa.sin_addr.s_addr = INADDR_ANY; # IPv4 bind addr\nstruct sockaddr_un sun; sun.sun_family = AF_UNIX; strcpy(sun.sun_path, \"/tmp/s.sock\"); # Unix socket path\nstruct sockaddr_storage ss; socklen_t len = sizeof(ss); recvfrom(fd, buf, len, 0, (struct sockaddr *)&ss, &len); # Generic storage\n# Always use htons()/htonl() for port/IP fields to ensure network byte order.","section":"3","section_name":"Library Functions","categories":["networking","development","ipc"],"use_frequency":5,"package":"manpages-dev"},{"id":101858,"name":"sockaddr, sockaddr_storage, sockaddr_in, sockaddr_in6, sockaddr_un, socklen_t, in_addr, in6_addr, in_addr_t, in_port_t,","one_liner":"Data structures used for socket addressing and network communication in C.","card":"struct sockaddr_in addr; memset(&addr, 0, sizeof(addr)); addr.sin_family = AF_INET; addr.sin_port = htons(8080); inet_pton(AF_INET, \"127.0.0.1\", &addr.sin_addr); # Configure IPv4 addr\nstruct sockaddr_un un; un.sun_family = AF_UNIX; strcpy(un.sun_path, \"/tmp/s.sock\"); # Configure UNIX socket\nstruct sockaddr_storage ss; socklen_t len = sizeof(ss); recvfrom(fd, &ss, len, 0, (struct sockaddr*)&ss, &len); # Use storage for protocol agnostic code\n# Use htons() for ports and htonl() for IPs to ensure network byte order.","section":"3","section_name":"Library Functions","categories":["networking","development","ipc"],"use_frequency":5,"package":"manpages-dev"},{"id":120215,"name":"sockaddr, sockaddr_storage, sockaddr_in, sockaddr_in6, sockaddr_un, socklen_t, in_addr, in6_addr, in_addr_t, in_port_t,","one_liner":"Core data structures for defining socket addresses across various network and local protocols.","card":"struct sockaddr_in addr; memset(&addr, 0, sizeof(addr)); addr.sin_family = AF_INET; addr.sin_port = htons(8080); addr.sin_addr.s_addr = INADDR_ANY; # IPv4 setup\nstruct sockaddr_un un; un.sun_family = AF_UNIX; strcpy(un.sun_path, \"/tmp/s.sock\"); # UNIX domain setup\nbind(fd, (struct sockaddr *)&addr, sizeof(addr)); # Casting generic sockaddr\nconnect(fd, (struct sockaddr *)&un, sizeof(un)); # Using local path sockets\n// Always use sockaddr_storage when address type is unknown at compile-time.","section":"3","section_name":"Library Functions","categories":["networking","development","ipc"],"use_frequency":5,"package":"manpages-dev"}],"total":147,"limit":20,"offset":0}