Files, Archives & File Editors
Overview
This reference covers the most common file operations on Linux: creating, reading, searching, and editing files; compressing and archiving with tar and friends; text processing with sed, awk, and grep; and essential Vim editor commands. It also catalogs the standard directory hierarchy on Debian-based systems.
Standard file locations
Filesystem hierarchy
| Directory | Purpose |
|---|---|
/bin/ | Essential user command binaries. |
/sbin/ | System administration binaries. |
/usr/bin/ | Non-essential user binaries. |
/usr/sbin/ | Non-essential system binaries. |
/usr/local/bin/ | Locally installed user binaries. |
/etc/ | System-wide configuration files. |
/var/log/ | Log files. |
/var/lib/ | Variable state data (databases, package data). |
/tmp/ | Temporary files (cleared on reboot). |
/var/tmp/ | Temporary files (persist across reboots). |
/opt/ | Add-on application packages. |
/home/ | User home directories. |
/root/ | Root user home directory. |
/boot/ | Kernel images and bootloader files. |
/proc/ | Virtual filesystem for kernel/process info. |
/sys/ | Virtual filesystem for device/kernel parameters. |
/dev/ | Device nodes. |
/run/ | Runtime variable data (temporary since last boot). |
/srv/ | Data served by the system (e.g., web root). |
CRUD operations
Creating files and directories
touch creates empty files (or updates their timestamps), and mkdir creates directories. Brace expansion and the -p flag cover multiple files and nested paths in one command.
touch file.txt # create empty file
touch file{1,2,3}.txt # create multiple files
mkdir newdir # create directory
mkdir -p a/b/c # create nested directories
Reading files
Several tools read files depending on the need: cat dumps a whole file, less pages through large ones, and head/tail view just the beginning or the end.
cat file.txt # print entire file
cat -n file.txt # with line numbers
less file.txt # paginated view (q to quit)
more file.txt # basic pagination (legacy)
head -n 20 file.txt # first 20 lines
tail -n 20 file.txt # last 20 lines
tail -f /var/log/syslog # follow file as it grows
tail -F /var/log/syslog # follow, reopens on rotation
nl file.txt # number lines
Copying, moving, deleting
cp, mv, and rm are the core file operations. Their flags control recursion, preservation of attributes, and safety prompts before overwriting.
cp source.txt dest.txt # copy file
cp -r sourcedir/ destdir/ # copy directory recursively
cp -p source.txt dest.txt # preserve attributes
cp -u source.txt dest.txt # copy only if source is newer
mv oldname.txt newname.txt # rename/move
mv file.txt /dest/path/ # move to directory
mv -i file.txt /dest/path/ # prompt before overwriting
rm file.txt # remove file
rm -rf somedir/ # recursive force remove (dangerous)
rmdir emptydir/ # remove empty directory
Linking files
Links create additional names for the same file. A symbolic link points to a path and breaks if the target moves; a hard link points directly at the file's data and only breaks when the last link to it is removed.
ln -s /actual/path/file.txt link.txt # symbolic link (soft link)
ln /actual/path/file.txt hardlink.txt # hard link
ls -l link.txt # see symlink target
readlink -f link.txt # resolve full path of symlink
Bind mounts (solving traversal permission errors)
Symlinks resolve through every parent directory in the chain — if any of them are inaccessible to a user or process, the link fails. A bind mount sidesteps this by attaching the target directory directly at a publicly reachable mount point, avoiding the private path entirely.
# Create a shared access point and bind-mount the private directory there
sudo mkdir -p /srv/shared-app
sudo mount --bind /home/alice/projects/myapp /srv/shared-app
# Verify the mount
mount | grep /srv/shared-app
# /home/alice/projects/myapp on /srv/shared-app type none (rw,bind)
# Make it persistent (survives reboot) via /etc/fstab:
# /home/alice/projects/myapp /srv/shared-app none bind 0 0
Now any user or container that can reach /srv/shared-app has access to the contents — no
Permission denied errors from intermediate directories like /home/alice.
Cleanup:
sudo umount /srv/shared-app
File comparison
diff compares files line by line and directories recursively, producing output that can feed patch. comm compares two sorted files and reports lines unique to each or shared by both.
diff file1.txt file2.txt # line-by-line differences
diff -u file1.txt file2.txt # unified diff format (patch-compatible)
diff -r dir1/ dir2/ # recursive directory comparison
colordiff file1.txt file2.txt # colorized diff (install colordiff)
comm file1.txt file2.txt # compare sorted files (columns: unique-to-1, unique-to-2, common)
File permissions (quick reference)
These one-liners cover the permission and ownership changes you will use daily. chmod sets mode bits, while chown and chgrp set ownership.
chmod 755 script.sh # rwxr-xr-x
chmod 644 file.txt # rw-r--r--
chmod 600 id_rsa # rw-------
chmod 700 ~/.ssh # rwx------
chown user:group file.txt # change owner and group
chown -R user:group /opt/app # recursive
chgrp group file.txt # change group
See the full Users & Permissions reference for complete details.
Finding and searching
find
find searches a directory tree by name, type, size, modification time, user, or permissions — and can run a command on every match.
find /var/log -name "*.log" # by filename pattern
find /var/log -name "*.log" -type f # files only (not directories)
find /home -name "*.txt" -mtime -7 # modified in last 7 days
find /tmp -name "*.tmp" -mtime +30 # older than 30 days
find / -type f -size +100M # larger than 100 MB
find / -type f -size +1G 2>/dev/null # suppress permission errors
# Execute actions on found files
find . -name "*.bak" -delete # delete found files
find . -name "*.log" -exec gzip {} \; # gzip each file
find . -name "*.log" -exec mv {} /backup/ \; # move each file
# Complex conditions
find /var -type f \( -name "*.log" -o -name "*.txt" \) -mtime -1
# Exclude directory
find /var -not -path "*/cache/*" -name "*.log"
# By user/group
find /home -user jdoe
find /home -group developers
# By permissions
find / -perm 777 -type f
find / -perm -u+s # files with SUID bit
grep
grep searches text for patterns, by default printing the matching lines. Flags control case sensitivity, recursion, context, and the shape of the output.
grep "pattern" file.txt # basic search
grep -i "pattern" file.txt # case-insensitive
grep -r "pattern" /etc/ # recursive search
grep -rl "pattern" /etc/ # list matching files (not content)
grep -rn "pattern" /etc/ # with line numbers
grep -v "pattern" file.txt # invert match (exclude)
grep -c "pattern" file.txt # count matches
grep -E "pat1|pat2" file.txt # extended regex (OR)
grep -A2 -B3 "pattern" file.txt # 3 lines before, 2 after
grep -w "word" file.txt # whole word only
grep -o "pattern" file.txt # only matching text
# With file types
grep --include="*.log" -rn "error" /var/log/
grep --exclude="*.gz" -rn "error" /var/log/
locate (fast, uses an index database)
locate finds files by name almost instantly by querying a prebuilt database. updatedb rebuilds that database, so locate only sees files indexed since the last run.
updatedb # update the file database
locate nginx.conf # find files by name
locate -i nginx # case-insensitive
locate -r '\.conf$' # regex match
which / whereis / type
These three commands tell you what a command name resolves to: which searches PATH, whereis also finds the binary's docs and sources, and type shows how the shell itself interprets the name.
which python # locate a command in PATH
whereis python # find binary, source, and man page
type python # show how the shell would interpret the command
Archives and compression
tar
tar bundles files and directories into a single archive, with optional gzip, bzip2, or xz compression. The same f flag selects the archive file for creating, extracting, and listing.
# Create archives
tar -czf archive.tar.gz dir/ # create gzipped tar
tar -cjf archive.tar.bz2 dir/ # create bzip2 compressed tar
tar -cJf archive.tar.xz dir/ # create xz compressed tar
tar -cf archive.tar dir/ # create uncompressed tar
# Extract archives
tar -xzf archive.tar.gz # extract gzipped tar
tar -xjf archive.tar.bz2 # extract bzip2 tar
tar -xJf archive.tar.xz # extract xz tar
tar -xf archive.tar # auto-detect compression
# List contents
tar -tzf archive.tar.gz # list without extracting
tar -tvf archive.tar # verbose listing
# Extract to specific directory
tar -xzf archive.tar.gz -C /dest/path/
# Common flags
# c = create, x = extract, t = list
# v = verbose, f = file, C = change directory
# z = gzip, j = bzip2, J = xz
# Exclude patterns
tar -czf backup.tar.gz dir/ --exclude='*.log' --exclude='node_modules'
Compression utilities
Standalone compression tools compress a single file at a time — gzip, bzip2, and xz are common on Linux, while zip packages multiple files and is portable to other systems.
# gzip / gunzip
gzip file.txt # compress to file.txt.gz
gunzip file.txt.gz # decompress
gzip -k file.txt # keep original
gzip -1 file.txt # fastest (least compression)
gzip -9 file.txt # best compression
# bzip2 / bunzip2
bzip2 file.txt
bunzip2 file.txt.bz2
# xz
xz file.txt
unxz file.txt.xz
# zip / unzip (cross-platform)
zip archive.zip file1.txt file2.txt
zip -r archive.zip dir/
unzip archive.zip
unzip -l archive.zip # list contents
Other archive tools
7z and rar handle the proprietary archive formats of the same names, which you may receive from or need to send to Windows users.
# 7z (install p7zip-full)
7z a archive.7z dir/ # create 7z archive
7z x archive.7z # extract with full paths
7z l archive.7z # list contents
# rar (install rar/unrar)
rar a archive.rar dir/
unrar x archive.rar
Text processing
sed (stream editor)
sed edits text streams line by line. Its most common operations are substitution (s/old/new/), deletion, printing selected lines, and insert/append.
# Substitution
sed 's/old/new/' file.txt # replace first occurrence per line
sed 's/old/new/g' file.txt # replace all occurrences per line
sed 's/old/new/gi' file.txt # case-insensitive, all
sed 's/old/new/2' file.txt # replace 2nd occurrence only
# In-place editing
sed -i 's/foo/bar/g' file.txt # edit file directly
sed -i.bak 's/foo/bar/g' file.txt # create backup with .bak extension
# Delete lines
sed '5d' file.txt # delete line 5
sed '5,10d' file.txt # delete lines 5-10
sed '/pattern/d' file.txt # delete matching lines
sed '/^$/d' file.txt # delete blank lines
sed '/^#/d' file.txt # delete comment lines
# Print lines
sed -n '5p' file.txt # print line 5
sed -n '5,10p' file.txt # print lines 5-10
sed -n '/pattern/p' file.txt # print matching lines
# Insert/append
sed '5i\new line before line 5' file.txt # insert before
sed '5a\new line after line 5' file.txt # append after
# Multiple commands
sed -e 's/foo/bar/g' -e 's/baz/qux/g' file.txt
# Capture groups
sed 's/\([0-9]*\)-\([0-9]*\)/\2-\1/' file.txt # swap captured groups
awk
awk is a text-processing language built around columns. It can extract fields, filter rows by conditions, accumulate summaries, and format output.
# Column extraction
awk '{print $1}' file.txt # first column
awk '{print $1, $3}' file.txt # columns 1 and 3
awk -F: '{print $1, $7}' /etc/passwd # custom delimiter
awk -F, '{print $NF}' file.csv # last column
# Filtering
awk '$3 > 100 {print $1, $3}' file.txt # conditional
awk '/pattern/ {print $1}' file.txt # pattern match
awk 'NR>=5 && NR<=10 {print}' file.txt # line range
# Summaries and calculations
awk '{sum+=$2} END {print "Total:", sum}' file.txt # sum column
awk '{count++} END {print count}' file.txt # count lines
awk '{max=($1>max ? $1 : max)} END {print max}' # maximum value
awk '{ips[$1]++} END {for(ip in ips) print ip, ips[ip]}' # count occurrences
# Formatting
awk '{printf "%-20s %10d\n", $1, $2}' file.txt # formatted output
cut, sort, uniq, wc
These small tools chain together for common text tasks: cut extracts fields or character ranges, sort orders lines, uniq collapses duplicates, and wc counts lines, words, or bytes.
cut -d':' -f1,7 /etc/passwd # extract fields by delimiter
cut -c1-10 file.txt # extract character ranges
sort file.txt # sort lines alphabetically
sort -n file.txt # numeric sort
sort -rn file.txt # reverse numeric sort
sort -t':' -k3 -n /etc/passwd # sort by field, numeric
sort -u file.txt # unique sort (remove duplicates)
uniq sorted_file.txt # remove adjacent duplicates
uniq -c sorted_file.txt # count occurrences
uniq -d sorted_file.txt # show only duplicates
sort file.txt | uniq -c | sort -rn # frequency count (descending)
wc file.txt # lines, words, bytes
wc -l file.txt # line count only
wc -w file.txt # word count only
wc -c file.txt # byte count only
Vim essentials
Modes
| Mode | How to enter | Purpose |
|---|---|---|
| Normal | Esc (default) | Navigation and commands |
| Insert | i, a, o, I, A, O | Typing text |
| Visual | v, V, Ctrl+v | Selecting text |
| Command | : | Ex commands (save, quit, search) |
Navigation
Move through a file quickly with single-key motions: word jumps, line starts and ends, page scrolls, and jump-to-line.
h j k l " left, down, up, right
w " next word
b " previous word
0 " start of line
^ " first non-blank character
$ " end of line
gg " top of file
G " bottom of file
:42 " go to line 42
Ctrl+f " page down (forward)
Ctrl+b " page up (backward)
% " jump to matching bracket
Editing
Normal-mode keys insert, delete, and change text without reaching for the mouse: d cuts, y yanks, p pastes, and u/Ctrl+r undo and redo.
i " insert before cursor
a " insert after cursor
I " insert at start of line
A " insert at end of line
o " open new line below
O " open new line above
dd " delete (cut) line
dw " delete word
D " delete to end of line
yy " yank (copy) line
yw " yank word
p " paste after cursor
P " paste before cursor
u " undo
Ctrl+r " redo
. " repeat last change
r " replace single character
>> " indent line
<< " un-indent line
Visual mode
Visual mode selects a block of text before acting on it — character-wise, line-wise, or as a rectangular block — then delete, yank, change, or indent the selection.
v " character-wise selection
V " line-wise selection
Ctrl+v " block selection
d / y / c " delete / yank / change selection
> " indent selection
Search and replace
Search forward and backward with / and ?, then scope a substitution with :s to a line, the whole file, or a line range — with optional confirmation.
/pattern " search forward
?pattern " search backward
n " next match
N " previous match
* " search word under cursor
:s/old/new/g " replace in current line
:%s/old/new/g " replace in entire file
:%s/old/new/gc " replace with confirmation
:5,10s/old/new/g " replace in lines 5-10
File operations
Ex commands handle saving and opening files: write the buffer, quit the editor, save under a new name, or switch to another file.
:w " save (write)
:q " quit
:wq " save and quit
:x " save and quit (only if changed)
:q! " quit without saving
:w newfile.txt " save as new file
:e file.txt " open/edit another file
Window splitting
Split the window to view multiple files side by side, switching between splits with Ctrl+w.
:vsp file.txt " vertical split
:sp file.txt " horizontal split
Ctrl+w w " switch between splits
Ctrl+w q " close split
:only " close all other splits
Vim configuration
Settings in ~/.vimrc apply on every startup. set options control line numbers, indentation behavior, and search highlighting.
# ~/.vimrc
set number " show line numbers
set relativenumber " relative line numbers
set expandtab " use spaces instead of tabs
set tabstop=4 " tab width
set shiftwidth=4 " indent width
set autoindent " auto-indent new lines
set hlsearch " highlight search results
set incsearch " incremental search
set ignorecase smartcase " case-insensitive unless uppercase is used
syntax on " syntax highlighting