Reference
linesieve
linesieve is a tool for splitting text input into sections and applying filters to the lines in each section.
Example:
$ ls -1 /* | linesieve -s '.*:' show bin match ^d head -n2
.....
/bin:
dash
date
......
/sbin:
disklabel
dmesg
...
You can specify a section marker regex with -s/--section
,
as well as --success
and --failure
markers
which cause linesieve to exit early.
To show only specific sections, use the show
subcommand;
skipped sections are marked with a dot on stderr.
$ ls -1 /* | linesieve -s '.*:' --failure ^cat show bin
.....
/bin:
[
bash
cat
All patterns use the Python regular expression syntax.
You can use subcommands to filter the lines in each section.
To restrict a filter to specific sections,
use their -s/--section
option;
you can also temporarily restrict all filters
using the push
and pop
subcommands.
$ ls -1 /* | linesieve -s '.*:' show bin \
> match -s /bin ^b match -s /sbin ^d head -n1
.....
/bin:
bash
......
/sbin:
disklabel
...
By default, linesieve reads from the standard input,
but it can also read from a file or a command
with the read
and read-cmd
subcommands.
$ linesieve read-cmd echo bonjour
bonjour
linesieve: echo exited with status code 0
On output, runs of blank lines are collapsed into a single line.
linesieve [OPTIONS] [COMMAND [ARGS]...]...
Options
- -s, --section <PATTERN>
Consider matching lines the start of a new section. The section name is one of: the named group
name
, the first captured group, the entire match.
- --success <PATTERN>
If matched, exit with a status code indicating success.
- --failure <PATTERN>
If matched, exit with a status code indicating failure. Before exiting, output the last section if it wasn’t already.
- --version
Show the version and exit.
head
Print the first COUNT lines.
Roughly equivalent to: head -n COUNT
$ echo -e 'a\nb\nc' | linesieve head -n2
a
b
linesieve head [OPTIONS]
Options
- -n <COUNT>
Print the first COUNT lines. With a leading
-
, print all but the last COUNT lines.- Default:
10
- -s, --section <PATTERN>
Apply only to matching sections. If there are patterns on the section stack, push the pattern (that is, apply also to matching sections).
help
Show detailed help.
linesieve help [OPTIONS]
Options
- --all
Show help for all commands, man-style.
hide
Do not output sections matching PATTERN.
hide
patterns take priority over show
patterns.
^$
matches the lines before the first section.
$none
matches no section.
$ ls -1 /* | linesieve -s '.*:' show bin hide /bin head -n2
............
/sbin:
apfs_hfs_convert
disklabel
...
linesieve hide [OPTIONS] PATTERN
Options
- -X, --verbose
Ignore whitespace and comments in the pattern.
- -i, --ignore-case
Perform case-insensitive matching.
- -F, --fixed-strings
Interpret the pattern as a fixed string.
Arguments
- PATTERN
Required argument
match
Output only lines matching PATTERN.
Roughly equivalent to: grep PATTERN
Works like re.search() in Python.
$ seq 10 | linesieve match 1
1
10
$ echo a1b2c3 | linesieve match -o '\d+'
1
2
3
linesieve match [OPTIONS] PATTERN
Options
- -X, --verbose
Ignore whitespace and comments in the pattern.
- -i, --ignore-case
Perform case-insensitive matching.
- -F, --fixed-strings
Interpret the pattern as a fixed string.
- -o, --only-matching
Output only the matching part of the line, one match per line. Works like re.findall() in Python: if there are no groups, output the entire match; if there is one group, output the group; if there are multiple groups, output all of them (tab-separated).
- -v, --invert-match
Output only lines not matching the pattern.
- --color
Color matches.
- -s, --section <PATTERN>
Apply only to matching sections. If there are patterns on the section stack, push the pattern (that is, apply also to matching sections).
Arguments
- PATTERN
Required argument
pipe
Pipe lines to COMMAND and replace them with the output.
COMMAND is executed once per section.
$ echo a-b | linesieve pipe 'tr -d -'
ab
linesieve pipe [OPTIONS] COMMAND
Options
- -s, --section <PATTERN>
Apply only to matching sections. If there are patterns on the section stack, push the pattern (that is, apply also to matching sections).
Arguments
- COMMAND
Required argument
pop
Pop patterns off the section stack. See ‘push’ for details.
With no arguments, removes the top pattern from the stack.
linesieve pop [OPTIONS]
Options
- -a, --all
Remove all the patterns from the stack.
push
Push a pattern onto the section stack.
When there are patterns on the section stack, filters apply only to the sections that match any of the patterns in the stack.
filter --section PATTERN
is equivalent to
push PATTERN filter pop
.
$ ls -1 /* | linesieve -s '.*:' \
> show bin \
> push /bin \
> head -n1 \
> pop \
> head -n2
.....
/bin:
[
......
/sbin:
apfs_hfs_convert
disklabel
...
linesieve push [OPTIONS] PATTERN
Options
- -X, --verbose
Ignore whitespace and comments in the pattern.
- -i, --ignore-case
Perform case-insensitive matching.
- -F, --fixed-strings
Interpret the pattern as a fixed string.
Arguments
- PATTERN
Required argument
read
Read input from FILE instead of standard input.
Roughly equivalent to: linesieve < FILE
$ linesieve read file.txt
hello
linesieve read [OPTIONS] FILE
Arguments
- FILE
Required argument
read-cmd
Execute COMMAND and use its output as input.
Roughly equivalent to: COMMAND | linesieve
If the command finishes, exit with its status code.
$ linesieve read-cmd echo bonjour
bonjour
linesieve: echo exited with status code 0
linesieve read-cmd [OPTIONS] COMMAND [ARGUMENT]...
Arguments
- COMMAND
Required argument
- ARGUMENT
Optional argument(s)
show
Output only sections matching PATTERN.
hide
patterns take priority over show
patterns.
^$
matches the lines before the first section.
$none
matches no section.
$ ls -1 /* | linesieve -s '.*:' show /bin match ash
.....
/bin:
bash
dash
..........
linesieve show [OPTIONS] PATTERN
Options
- -X, --verbose
Ignore whitespace and comments in the pattern.
- -i, --ignore-case
Perform case-insensitive matching.
- -F, --fixed-strings
Interpret the pattern as a fixed string.
Arguments
- PATTERN
Required argument
span
Output only lines between those matching --start
and --end
.
Roughly equivalent to: grep START -A9999 | grep END -B9999 | head -n-1
$ seq 20 | linesieve span --start ^2$ --end ^5$ --repl ...
...
2
3
4
...
linesieve span [OPTIONS]
Options
- --start, --start-with <PATTERN>
Span start (inclusive).
- --end, --end-before <PATTERN>
Span end (exclusive).
- -X, --verbose
Ignore whitespace and comments in the pattern.
- -i, --ignore-case
Perform case-insensitive matching.
- -F, --fixed-strings
Interpret the pattern as a fixed string.
- -v, --invert-match
Output only lines not between those matching
--start
and--end
.
- --repl, --replacement <repl>
Replace non-matching line spans with TEXT. With
--invert-match
, backreferences to captures in--start
are expanded; without--invert-match
, only escapes are expanded.
- -s, --section <PATTERN>
Apply only to matching sections. If there are patterns on the section stack, push the pattern (that is, apply also to matching sections).
split
Print selected parts of lines.
Roughly equivalent to:
awk '{ print ... }' (no --delimiter)
cut -d delim (--fixed-strings --delimiter delim)
Python equivalents:
line.split() (no --delimiter)
line.split(delim) (--fixed-strings --delimiter delim)
re.split(delim, line) (--delimiter delim)
--fields
takes a comma-separated list of ranges, each range one of:
N Nth field, counted from 1
N- from Nth field to end of line
N-M from Nth to Mth (included) field
-M from first to Mth (included) field
This is the same as the cut command. Unlike cut, selected fields are printed in the order from the list, and more than once, if repeated.
$ echo -e 'a-b\nc-d' | linesieve split -d- -f2
b
d
linesieve split [OPTIONS]
Options
- -d, --delimiter <PATTERN>
Use as field delimiter (consecutive delimiters delimit empty strings). If not given, use runs of whitespace as a delimiter (with leading/trailing whitespace stripped first).
- -X, --verbose
Ignore whitespace and comments in the pattern.
- -i, --ignore-case
Perform case-insensitive matching.
- -F, --fixed-strings
Interpret the pattern as a fixed string.
- -n, --max-split <INTEGER>
Maximum number of splits to do. The default is no limit.
- -f, --fields <LIST>
Select only these fields.
- -D, --output-delimiter <output_delimiter>
Use as the output field delimiter. If not given, and
--delimiter
and--fixed-strings
are given, use the input delimiter. Otherwise, use one tab character.
- -s, --section <PATTERN>
Apply only to matching sections. If there are patterns on the section stack, push the pattern (that is, apply also to matching sections).
sub
Replace PATTERN matches with REPL.
Roughly equivalent to: sed 's/PATTERN/REPL/g'
Works like re.sub() in Python.
$ echo a1b2c3 | linesieve sub '\d+' x
axbxcx
linesieve sub [OPTIONS] PATTERN REPL
Options
- -X, --verbose
Ignore whitespace and comments in the pattern.
- -i, --ignore-case
Perform case-insensitive matching.
- -F, --fixed-strings
Interpret the pattern as a fixed string.
- -o, --only-matching
Output only matching lines.
- --color
Color replacements.
- -s, --section <PATTERN>
Apply only to matching sections. If there are patterns on the section stack, push the pattern (that is, apply also to matching sections).
Arguments
- PATTERN
Required argument
- REPL
Required argument
sub-cwd
Make absolute paths in the working directory relative.
Roughly equivalent to: sub $( pwd ) ''
$ echo "hello from $( pwd )/src" | linesieve sub-cwd
hello from src
linesieve sub-cwd [OPTIONS]
Options
- -s, --section <PATTERN>
Apply only to matching sections. If there are patterns on the section stack, push the pattern (that is, apply also to matching sections).
sub-link
Replace the target of symlink LINK with LINK.
Roughly equivalent to: sub $( realpath LINK ) LINK
linesieve sub-link [OPTIONS] LINK
Options
- -s, --section <PATTERN>
Apply only to matching sections. If there are patterns on the section stack, push the pattern (that is, apply also to matching sections).
Arguments
- LINK
Required argument
sub-paths
Replace paths of existing files with shorter versions.
The replacement paths are still unique.
For example, given these files are selected:
src/one/mod1.py
src/one/two/mod2.py
tests/test.py
Their paths will be replaced with:
.../mod1.py
.../mod2.py
.../test.py
Dotted module names derived from the selected files can also be shortened.
For example, with --modules-skip 1 --modules-recursive
, these modules:
one.mod1
one.two.mod2
one.two
Will be replaced with:
..mod1
..mod2
..two
linesieve sub-paths [OPTIONS]
Options
- --include <GLOB>
Replace the paths of existing files matching this pattern. Both recursive globs and brace expansion are supported, e.g.
{src,tests}/**/*.py
.
- --modules
Also replace dotted module names.
- --modules-skip <INTEGER>
Path levels to skip to obtain module names from paths. Implies
--modules
.
- --modules-recursive
Consider the parent directories of selected files to be modules too. Implies
--modules
.
- -s, --section <PATTERN>
Apply only to matching sections. If there are patterns on the section stack, push the pattern (that is, apply also to matching sections).
tail
Print the last COUNT lines.
Roughly equivalent to: tail -n COUNT
$ echo -e 'a\nb\nc' | linesieve tail -n2
b
c
linesieve tail [OPTIONS]
Options
- -n <COUNT>
Print the last COUNT lines. With a leading
+
, print lines starting with line COUNT.- Default:
10
- -s, --section <PATTERN>
Apply only to matching sections. If there are patterns on the section stack, push the pattern (that is, apply also to matching sections).