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As you're focused on the command line, I won't mention things I generally use in shell scripts like compound commands (if, for, while) or shell parameters. I will also skip things I don't often use. First, there is moving around in bash - the arrow keys, or backspace/delete to remove a character, or ^A to go to line start, or ^R to search command history, or tab to complete a command. ^L clears the screen, although from habit I still type clear. I use shell/bash builtins cd, and pwd often enough. Sometimes export, umask, exit, ulimit -a, echo. I use shell variables like PS1, HOME, and PATH. I set them in $HOME/.bashrc, which sometimes references files like $HOME/.bash_aliases. I often set a larger than default history file size. I use ~ tilde expansion as an abbreviation for $HOME. For long commands I type regularly, I put an alias in the run control (or run control delegated) file. I use job control commands like bg, fg, jobs and kill. You should know how bash job control complements and diverges from the system process commands. & starts a process as a background process, and preceding it from nohup tells it to ignore hangup signals. You should know how single quotes work, and escape characters for them if they are needed. Then there are pipes (| - "pipelines"), and redirecting of stdin, stdout, and stderr. I use this a lot. Also redirecting or appending output to a file (>, >>). I don't use tee often but sometimes do. Then there are commands used with the shell a lot. Such as parallel, or xargs. Also nice which modifies process scheduling. Script, or typescript, keeps a log of your shell session. Screen allows for multiple shell sessions. Useful on remote hosts especially (tmux is an alternative). Then there are the standard file and directory commands I often use like pwd, cd, ls, mv, cp, df, chmod, du, file, find, locate, mkdir, touch, rm, which, and wc. I manipulate these with commands like awk, sed, tr, grep, egrep, cat, head, tail, diff, and less. I edit with vim or emacs -nw. Command like htop, ps, w, uptime and kill let me deal with system processes. Then there are just handy commands like bc or cal if I need to do some simple addition or see which day of the week the first of the month is. Man shows you manual pages for various commands. "man command" will show the manual page. For a command like kill, the default will show the command kill - "man kill" which specifically is "man 1 kill". But "man 2 kill" would show the kill system call. You can see what these different manual sections are with "man man" - 1 is executable programs, 2 is system calls etc. All of it is a process. I mentioned awk. It is one of the commands handy to use with the shell. I have seen entire programs written in awk. Some parts of awk I can use from memory, some I use occasionally and have to look up the flags to refresh my memory, some parts I have never used at all. As time goes on you pick up more and more as you need it. |