Linux sed and awk Cheat Sheet

Linux Text Processing•Permalink

Edit text streams with sed and parse structured text with awk.

View

Standard Detailed Compact

Export

Copy the compact sheet, download it, or print it.

Download

`D` dense toggle · `C` copy all

sed Substitution

Replace text patterns line by line.

Replace first occurrence per line

Substitute one match in each line.

↗#

bashANYsedreplace

bash

sed 's/foo/bar/' file.txt

By default, sed replaces only the first match on each line.

Replace all occurrences per line

Substitute every match on each line.

↗#

bashANYsedreplaceglobal

bash

sed 's/foo/bar/g' file.txt

The `g` flag applies the replacement globally across the line.

Edit a file in place

Modify the original file directly.

↗#

bashANYsedin-place

bash

sed -i 's/debug/info/g' app.conf

In-place editing is powerful; consider keeping backups before bulk changes.

Edit in place with backup

Create a backup copy while editing.

↗#

bashANYsedbackupin-place

bash

sed -i.bak 's/debug/info/g' app.conf

Creates `app.conf.bak` before replacing the original file.

Use an alternate delimiter

Make path replacements easier to read.

↗#

bashANYseddelimiterpaths

bash

sed 's|/usr/local/bin|/opt/bin|g' paths.txt

Alternate delimiters reduce escaping when replacing file paths or URLs.

sed Line Deletion and Printing

Delete, print, and filter lines by patterns or ranges.

Delete blank lines

Remove empty lines from output.

↗#

bashANYseddeleteblank-lines

bash

sed '/^$/d' file.txt

A common cleanup step before diffing or processing text.

Delete comment lines

Skip lines that begin with `#`.

↗#

bashANYseddeletecomments

bash

sed '/^[[:space:]]*#/d' config.ini

Especially useful for previewing meaningful config lines only.

Print only matching lines

Use sed as a pattern filter.

↗#

bashANYsedprintfilter

bash

sed -n '/ERROR/p' app.log

Suppress default output with `-n`, then explicitly print matches.

Delete a line range

Remove lines 5 through 10.

↗#

bashANYseddeleterange

bash

sed '5,10d' file.txt

Ranges are useful for removing generated headers or blocks quickly.

Print a line range only

Show lines 5 through 10.

↗#

bashANYsedprintrange

bash

sed -n '5,10p' file.txt

A compact way to inspect a specific segment of a file.

awk Fields and Records

Split lines into fields and work with structured text.

Print selected columns

Show the first and third whitespace-delimited fields.

↗#

bashANYawkfieldscolumns

bash

awk '{print $1, $3}' access.log

Awk automatically splits input lines into fields using whitespace by default.

Use a custom field separator

Split CSV-like data on commas.

↗#

bashANYawkcsvdelimiter

bash

awk -F, '{print $1, $2}' users.csv

`-F` sets the input field separator.

Print the last field

Use NF to reference the final field on each line.

↗#

bashANYawkfieldsnf

bash

awk '{print $NF}' file.txt

`NF` is the number of fields in the current record.

Print line numbers with lines

Prefix each line with NR.

↗#

bashANYawkline-numbernr

bash

awk '{print NR ": " $0}' file.txt

`NR` is the current record number across all input.

Set output field separator

Join output fields with commas.

↗#

bashANYawkofsformatting

bash

awk 'BEGIN{OFS=","} {print $1, $2, $3}' file.txt

`OFS` controls how fields are separated when printed with commas in `print`.

awk Filtering and Aggregation

Filter rows and calculate totals, counts, and summaries.

Print rows matching a condition

Show lines where column 3 is greater than 100.

↗#

bashANYawkfilter

bash

awk '$3 > 100 {print $0}' metrics.txt

Awk's pattern-action style is ideal for tabular filtering.

Sum a numeric column

Add all values in the second field.

↗#

bashANYawksumaggregation

bash

awk '{sum += $2} END {print sum}' prices.txt

Use the END block for final reporting after all input is processed.

Calculate an average

Compute the average of a numeric field.

↗#

bashANYawkaverageaggregation

bash

awk '{sum += $2; count += 1} END {if (count) print sum / count}' prices.txt

Track totals and counts explicitly for derived values like averages.

Count rows by key

Count occurrences of the first field.

↗#

bashANYawkgroupingcount

bash

awk '{count[$1]++} END {for (k in count) print k, count[k]}' file.txt

Associative arrays make awk a lightweight grouping and summarization tool.

Find the maximum value

Track the highest number in a field.

↗#

bashANYawkmaxaggregation

bash

awk 'NR==1 || $2 > max {max=$2} END {print max}' values.txt

Awk is often enough for lightweight numeric analysis without needing a spreadsheet.

awk Scripting Patterns

Use BEGIN, END, and built-in variables effectively.

Use BEGIN and END blocks

Print headers and footers around processed output.

↗#

bashANYawkbeginend

bash

awk 'BEGIN{print "name,total"} {print $1 "," $2} END{print "done"}' report.txt

BEGIN runs before input, END runs after all input is consumed.

Process command output

Filter output from another command using awk.

↗#

bashANYawkpipelinecommand-output

bash

df -h | awk 'NR>1 {print $1, $5, $6}'

Awk is especially useful for command output with stable columns.

Match with regex in awk

Print only lines that match a regex.

↗#

bashANYawkregexfilter

bash

awk '/ERROR|WARN/' app.log

A pattern-only awk program prints matching lines by default.

Replace text in awk

Use `sub` and `gsub` for replacements.

↗#

bashANYawkreplacegsub

bash

awk '{gsub(/foo/, "bar"); print}' file.txt

`sub` replaces one match, while `gsub` replaces all matches in the current record.

Skip a header row

Ignore the first line of a delimited file.

↗#

bashANYawkheadercsv

bash

awk 'NR>1 {print $1, $2}' users.csv

Skipping headers is one of the most common awk patterns for CSV-like inputs.

More in Linux Text Processing

Linux Pipelines, xargs, split, diff, and Practical Recipes Cheat Sheet

Build practical shell pipelines, batch commands with xargs, compare files, and split or reshape data.

Linux cut, sort, uniq, tr, paste, join, and comm Cheat Sheet

Column extraction, sorting, deduplication, character translation, file combining, and list comparison.

Linux grep and ripgrep Cheat Sheet

Search text with grep, egrep, fgrep, and ripgrep including regex, file globs, recursion, and context.

Linux Text Processing Cheat Sheet

Core Linux text processing commands and shell patterns for searching, filtering, editing, formatting, and analyzing text files and streams.

Recommended next

No recommendations yet.

Browse all sheets →