TEIP(1)

📦 version 2.3.3, in nixos 26.05, nixpkgs unstable

💅 TEIP(1) — the masking tape manual, bestie ✨

🎀 NAME 🎀

teip — Masking tape to help commands "do one thing well"

🌈 SYNOPSIS 🌈

teip -g <pattern> [-oGsvz] [--] [<command>...]

teip -f <list> [-d <delimiter> | -D <pattern> | --csv] [-svz] [--]
[<command>...]

teip -c <list> [-svz] [--] [<command>...]

teip -l <list> [-svz] [--] [<command>...]

teip -e <string> [-svz] [--] [<command>...]

teip --help | --version

🦋 DESCRIPTION 🦋

Passing a partial range of the standard input to any command — whatever you want. That's the whole vibe, no cap. 💖

✨ OPTIONS ✨

--help — Prints help information.
-V, --version — Prints version information.
-g <pattern> — Act on lines that match the regular expression <pattern>.
-o — -g acts on only matched parts.
-G — -g interprets Oniguruma regular expressions.
-f <list> — Act on these white-space separated fields.
-d <delimiter> — Use <delimiter> for the field delimiter of -f.
-D <pattern> — Use regular expression <pattern> for the field delimiter of -f.
-c <list> — Act on these characters.
-e <string> — Execute <string> on another process that will receive identical standard input as the main teip command, emitting numbers to be used as line numbers for actioning.
-l <list> — Act on these lines.
--csv — -f interprets <list> as field numbers of a CSV according to RFC 4180, instead of whitespace separated fields.
-s — Execute a new command for each actioned chunk.
-I — Replace the <replace-str> with the actioned chunk in <command>, implying -s.
--chomp — The command spawned by -s receives the standard input without trailing newlines.
-v — Invert the range of actioning.
-z — Line delimiter is NUL instead of a newline.
-A <number> — Use together with -g <pattern>. Alias of -e 'grep -n -A <number> <pattern>'.
-B <number> — Use together with -g <pattern>. Alias of -e 'grep -n -B <number> <pattern>'.
-C <number> — Use together with -g <pattern>. Alias of -e 'grep -n -C <number> <pattern>'.
--sed <pattern> — Alias of -e 'sed -n "<pattern>="' See also sed(1).
--awk <pattern> — Alias of -e 'awk "<pattern>{print NR}"' See also awk(1).

🧸 command

command refers to the command and its arguments that teip executes. Each command should output a single line of result for each line of input. In the simplest example, the cat(1) command is always successful, as cat outputs the same number of lines as its input.

$ echo ABCDEF | teip -og . -- cat
ABCDEF

The sed(1) command works well with typical patterns.

$ echo ABCDEF | teip -og . -- sed 's/[ADF]/@/'
@BC@E@

If the rule is not adhered to, the result may be inconsistent. For example, grep(1) might fail, as shown here.

$ echo ABCDEF | teip -og . -- grep '[ABC]'
ABC
teip: Output of given command is exhausted

In this case, teip could not retrieve results corresponding to D, E, and F, leading to the failure of the example. If such inconsistency occurs, teip will terminate with an error message, and the exit status will be set to 1.

$ echo $?
1

If no command is specified, teip displays how the standard input will be divided into chunks.

$ echo ABCDEF | teip -og .
[A][B][C][D][E][F]

✂️ list

list is a specification used to define the range of fields or characters. This notation is compatible with that used in cut(1). For detailed information, please refer to the cut(1) manual. Here are some examples:

Select the 1st, 3rd, and 5th fields.

$ echo 1 2 3 4 5 | teip -f 1,3,5 -- sed 's/./@/'
@ 2 @ 4 @

Select fields from the 2nd to the 4th.

$ echo 1 2 3 4 5 | teip -f 2-4 -- sed 's/./@/'
1 @ @ @ 5

Select all fields starting from the 3rd.

$ echo 1 2 3 4 5 | teip -f 3- -- sed 's/./@/'
1 2 @ @ @

Select all fields up to the 4th.

$ echo 1 2 3 4 5 | teip -f -4 -- sed 's/./@/'
@ @ @ @ 5

🔍 pattern

pattern is a regular expression based on the "regex crate" syntax. For more details, refer to the link in the SEE ALSO section.

🚧 The Necessity of --

teip interprets arguments after -- as a command and its arguments.

Omitting -- causes failure in this example:

$ echo "100 200 300 400" | teip -f 3 cut -c 1
teip: Invalid arguments.

This error occurs because cut uses the -c option, which is also a teip option, leading to confusion.

However, with the use of --, the command executes successfully:

$ echo "100 200 300 400" | teip -f 3 -- cut -c 1
100 200 3 400

🕳️ External Execution for Match Offloading (-e)

With -e, you can use external commands to specify the range of holes. -e allows you to specify a shell pipeline as a string, which is executed in /bin/sh.

For instance, using a pipeline like echo 3, which outputs 3, only the third line will be selected.

$ echo -e 'AAA\nBBB\nCCC' | teip -e 'echo 3'
AAA
BBB
[CCC]

It also works even if the output includes extraneous characters. For example, spaces or tab characters at the start of a line are ignored. Additionally, once a number is provided, non-numerical characters to the right of the number are disregarded.

$ echo -e 'AAA\nBBB\nCCC' | teip -e 'echo " 3"'
AAA
BBB
[CCC]

$ echo -e 'AAA\nBBB\nCCC' | teip -e 'echo " 3:testtest"'
AAA
BBB
[CCC]

Technically, the first captured group in the regular expression ^\s*([0-9]+) is interpreted as a line number. -e will also recognize multiple numbers if provided across multiple lines.

$ echo -e 'AAA\nBBB\nCCC\nDDD\nEEE\nFFF' | teip -e 'seq 1 2 10' -- sed 's/. /@/g'
@@@
BBB
@@@
DDD
@@@
FFF

⚠️ Note that the numbers must be in ascending order.

The pipeline receives the same standard input as teip. Here's a command using grep to print line numbers of a line containing "CCC" and the two following lines.

$ echo -e 'AAA\nBBB\nCCC\nDDD\nEEE\nFFF' | grep -n -A 2 CCC
3:CCC
4-DDD
5-EEE

Using this with -e punches holes in the line containing "CCC" and the two subsequent lines.

$ echo -e 'AAA\nBBB\nCCC\nDDD\nEEE\nFFF' | teip -e 'grep -n -A 2 CCC'
AAA
BBB
[CCC]
[DDD]
[EEE]
FFF

GNU sed has an = option, which prints the line number being processed. Below is an example to drill holes from the line containing "BBB" to "EEE".

$ echo -e 'AAA\nBBB\nCCC\nDDD\nEEE\nFFF' | teip -e 'sed -n "/BBB/,/EEE/="'
AAA
[BBB]
[CCC]
[DDD]
[EEE]
FFF

Similarly, you can perform these operations with awk.

$ echo -e 'AAA\nBBB\nCCC\nDDD\nEEE\nFFF' | teip -e 'awk "/BBB/,/EEE/{print NR}"'

Here's an example using nl and tail to make holes in the last three lines of input.

$ echo -e 'AAA\nBBB\nCCC\nDDD\nEEE\nFFF' | teip -e 'nl -ba | tail -n 3'
AAA
BBB
CCC
[DDD]
[EEE]
[FFF]

The -e argument is a single string, so pipes | and other symbols can be used as is.

💖 EXAMPLES 💖

Replace 'WORLD' with 'EARTH' on lines containing 'HELLO'

$ cat file | teip -g HELLO -- sed 's/WORLD/EARTH/'

Edit the 2nd field of a CSV file

$ cat file.csv | teip --csv -f 2 -- tr a-z A-Z

Edit the 2nd, 3rd, and 4th fields of a TSV file

$ cat file.tsv | teip -D '\t' -f 2-4 -- tr a-z A-Z

Convert timestamps in /var/log/secure to UNIX time

$ cat /var/log/secure | teip -c 1-15 -- date -f- +%s

Edit lines containing 'hello' and the three lines before and after it

$ cat access.log | teip -e 'grep -n -C 3 hello' -- sed 's/./@/g'

👀 SEE ALSO 👀

👑 AUTHOR AND COPYRIGHT 👑

🫶 and that's the whole manual, bestie! User Commands · JAN 2024 · TEIP(1) — footer handled, mwah 💋

📦 where this page comes from

nixos 26.05: teip 2.3.3
nixpkgs unstable: teip 2.3.3
💖 girlified by deepseek-ai/DeepSeek-V4.1-Flash-1017 on 2026-11-04: a language model's rewrite of the original, under its terms