List (ls)

ls [options] [paths]

Format

Switch	Description
-1	One entry per line
-l	Long view
-o	Long view (without groups)
-C	Multicolumn (sorted horizontally)
-x	Multicolumn (sorted vertically)
—
-F	Add / after directories
-G	Color
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Options

| -R | Recurse |
| -a | Include hidden (dotfiles) |
| -A | Include hidden (but not . and …) |
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Sorting

Switch	Description
-r	reverse order
-S	sort by size
-t	sort by time modified
-u	sort by time accessed
-U	sort by time created
-c	sort by time status was changed
—
-h	Human-readable size (3k)
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Tail

tail [-F | -f | -r] [-bN | -cN | -nN] [file ...]

Modes

| -f | follow |
| -F | follow by filename (accounts for log rotation) |
| -r | Reverse order |
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Options

| -bN | N*512 bytes |
| -cN | N bytes |
| -nN | N lines |
| +N | Start from line N |
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Sudo

sudo [options] <command>

Listing

| -l | List allowed commands |
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Options

| -A | Use $SUDO_ASKPASS |
| -b | Run in background |
| -E | Preserve environment |
| -H | use target’s $HOME |
| -n | Don’t prompt for password |
| -P | Preserve group vector |
| -S | Read password from stdin |
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File descriptors

| -C fd | Close all open file descriptors |
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Prompt

| -p prompt | Custom prompt (-p “%p password:”) |
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Interactive

Switch	Description
-i [cmd]	Interactive shell without variables
-s [cmd]	Interactive shell
----
-u user	run as this user
-g group	run as this group
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Timestamp

| -v | revalidate timestamp for 5 mins |
| -k | invalidate timestamp |
| -K | just like -k |
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wc (Word count)

... | wc [options]

| -c | Bytes |
| -l | Lines |
| -m | Characters (incl multi-byte) |
| -w | Words |
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Search-and-replace in all files

perl -p -i -e 's/hello/HELLO/g' **/*

Grep

grep [options] [pattern] [file ...]

Options

Switch	Description
-A num	Print num lines of training context
----
-G	–basic-regexp (default)
-E	–extended-regexp
-P	–perl-regexp
----
-f file	–file (Get patterns for file)
-F	–fixed-strings
----
-h	–no-filename
-H	–with-filename
----
-l	–files-with-matches (just print filenames)
-L	–files-without-match
----
-r, -R	–recursive
-v	–invert-match
-i	–ignore-case
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Synonyms

egrep  =>  grep -E
fgrep  =>  grep -F