Competencies: CLI & Terminal > System Tools
System Tools
Body of Knowledge
| Topic | Description | Relevance | Career Tracks |
|---|---|---|---|
find |
File system search, predicates (-type, -name, -mtime), -exec, -print0 for safety, logical operators, pruning. |
Critical |
All Engineering |
xargs |
Command line construction from stdin, parallel execution (-P), null delimiter (-0), batching (-n), placeholders (-I{}). |
High |
SRE, DevOps, Automation |
curl |
URL transfers, HTTP methods, headers, authentication, JSON payloads, cookie handling, SSL options, --fail-with-body. |
Critical |
DevOps, API Developer, SRE |
wget |
File downloading, recursive mirroring, resume support, bandwidth limiting, website archival. |
Medium |
Systems Administrator, DevOps |
rsync |
Efficient file synchronization, delta transfers, --dry-run, excludes, remote sync over SSH, backup strategies. |
Critical |
Systems Administrator, DevOps, SRE |
SSH CLI |
Remote shell, ProxyJump, port forwarding (local/remote/dynamic), ControlMaster, agent forwarding, escape sequences. |
Critical |
All Engineering |
SSH Config |
Host aliases, identity files, proxy configuration, match blocks, connection reuse, jump hosts. |
High |
All Engineering |
strace/ltrace |
System call tracing, library call tracing, performance analysis, debugging, -p for running processes. |
High |
SRE, Systems Administrator, Developer |
lsof |
List open files, network connections by process, file locks, deleted files still open, port usage. |
High |
Systems Administrator, SRE |
ss/netstat |
Socket statistics, listening ports, established connections, process mapping, protocol filtering. |
High |
Network Engineer, Systems Administrator, SRE |
ps/top/htop |
Process listing, resource monitoring, process tree, interactive process management, custom output. |
Critical |
All Engineering |
systemctl/journalctl |
systemd service management, unit files, journal querying, boot logs, filtering, persistent journals. |
Critical |
Systems Administrator, DevOps, SRE |
Personal Status
| Topic | Level | Evidence | Active Projects | Gaps |
|---|---|---|---|---|
curl |
Advanced |
REST API interaction — custom headers, authentication, JSON payloads, response parsing; domus-api demo/validation scripts use curl for all 44 endpoints |
No HTTP/2 specific features, no WebSocket via curl |
|
find |
Proficient |
-exec, -type, -name, -mtime, -size, -print0 for xargs safety; multi-predicate with -o/-a; prune for directory exclusion |
Not yet fully internalized — still reference manual for complex predicates |
|
xargs |
Proficient |
Parallel (-P4), null-delimited (-0), batching (-n), placeholder (-I{}); pipeline composition with find |
No xargs for complex multi-argument commands, not fully automatic yet |
|
SSH CLI |
Advanced |
ProxyJump chains, port forwarding (local/remote/dynamic), ssh-agent, config management, ControlMaster multiplexing; Vault SSH-CA signed keys |
No SSH escape sequences mastery, no advanced tunneling patterns |