| Bash scripting

Bash scripting

2020-11-25 2014-01-01
Bash tests : [ ... -x ... ], [ ... = ... ], [[ ... =~ ... ]], ...
[ [[
2020-11-18 2013-01-31
Bash loops
exit, for, IFS, read, until, while
2020-10-20 2016-11-13
HowTo's of text and text files processing
2020-07-08 2015-12-10
Bash arrays
associative, indexed
2019-11-04 2018-11-23
cut vs awk : which is the fastest to extract data from a CSV ?
2019-05-21 2015-06-10
How to read command-line arguments in a script ?
getopts
2019-05-20
The while read construct
2019-05-10
The if then else fi construct
2019-02-15 2017-09-25
Bash functions
scope
2019-01-28 2018-07-03
How to convert a relative path into an absolute path to source from anywhere ?
import, include
2018-12-18
How to get a file modification date ?
2018-12-17 2018-11-08
How to write all the outputs of a script into a file ?
2018-12-17
How to detect whether a script is run interactively or not ?
2018-11-28
Script error : Bad substitution
2018-11-09 2013-01-31
Bash scripting : using the right shebang
#!/bin/sh, #!/bin/bash, #!/usr/bin/env bash
2018-02-23
How to return a value from a function ?
2017-10-09
The case esac construct
2017-10-05 2013-01-31
How to check the number of arguments passed to a script ?
2017-03-31 2014-12-10
"Variable variables" a.k.a dynamic variables
2016-11-15
How to interrupt a loop ?
break, continue, eval, exit, return
2016-01-29
How to test if a variable is an integer ?
2015-12-05
Variables holding a path in shell scripts
2015-09-29
How to load tuples in a shell script ?
2015-02-20 2015-02-16
How to use booleans in Bash ?
set, unset
2015-02-19 2013-01-31
How to "retry until success" ?
retry, until
2014-11-13 2013-12-04
Bash script flags
set

HowTo's of text and text files processing

2020-10-20 2017-02-23
How to insert a string before / after a line matching a pattern ?
sed
2020-07-08 2014-09-24
How to explode a string into an array ?
2020-06-22 2016-07-04
How to display the nth line after / before a match ?
awk
2020-01-23
How to generate a pin code with a specific length ?
2020-01-14 2015-08-04
How to generate a string made of repetitions of a character / substring ?
2019-12-11
How to alter a line when the previous line matches ?
2019-12-11 2019-03-08
How to remove multi-line comments ?
2019-07-18 2019-05-13
How to get a cascading list of owner + group + permissions for a specified file ?
2019-06-24
How to (re-)indent code automatically ?
2019-04-16
How to count lines matching a regex ?
awk
2019-04-09
How to find duplicate lines in a file ?
2019-02-27 2018-10-30
How to compare code snippets ?
2019-02-15
How to count occurrences of a character in a string ?
2019-01-24
How to escape single quotes within single-quoted strings ?
2019-01-07 2018-12-21
How to concatenate strings ?
+=
2018-12-20 2015-08-19
How to check a string against a list of values ?
case, for, regular expression
2018-12-11
How to match strings across lines ?
2018-12-07 2010-09-27
How to remove newline characters ?
sed
2018-12-06
How to transpose line to column / column to line ?
2018-12-06 2018-08-20
How to read a multiline variable line by line ?
process substitution, < <(...)
2018-11-21
How to remove trailing SPACEs ?
sed
2018-11-05
How to detect duplicate fields in a file ?
awk
2018-10-15
How to remove the line matching a regexp and the following one ?
2018-10-15
How to swap command-line arguments ?
2018-09-03
How to filter lines having duplicate fields ?
awk
2017-10-04
How to get the position of a character in a string ?
2017-04-12 2013-01-31
How to sum numbers ?
bc
2017-03-28
How to round floating numbers ?
awk
2017-03-27
How to display the xth, yth and zth lines of a stream of text ?
2017-03-16 2010-09-27
Negative matching
grep, sed
2017-03-08 2016-11-19
How to keep / remove the n leading / trailing characters of a string ?
2016-12-19 2010-09-27
Extract a substring with a RegExp
sed
2016-12-14
How to display the nth line of a file ?
sed
2016-02-03 2015-06-10
How to compare a variable against a list of characters ?
2016-01-28 2010-09-27
Remove all non-ASCII characters from file/string
sed
2016-01-28 2010-09-27
Remove ANSI colors codes
sed
2016-01-28 2010-09-27
Delete empty lines
sed
2016-01-28 2010-09-27
How to substitute the 1st occurrence only of a pattern in a stream ?
sed
2016-01-28 2010-09-27
Need to handle \n or \t strings ?
sed
2016-01-28 2010-09-27
Replace a string with a newline
sed
2016-01-15
How to perform search / replace on a specific line of a file ?
2015-12-29 2009-11-27
How to handle text file encoding and transcode between us-ascii, iso-8859-15, utf-8, ..., charsets ?
iconv, recode, Emacs
2015-12-15
How to parse a string character by character ?
2015-09-03
How to store a command into a variable ?
eval
2015-02-13 2014-10-17
How to remove the header line from a command output ?
2014-07-31
How to display the n leading / trailing characters from each line of a file ?