sed(1)

sed [opts] [script] [file]
-  opts:
-    -i          edit file in place
-    -i.bk       edit file in place and create backup file
-                (with .bk suffix, can be specified differently)
-    --follow-symlinks
-                follow symlinks when editing in place
-    -e SCRIPT   add SCRIPT to commands to be executed
-                (can be specified multiple times)
-    -f FILE     add content of FILE to command to be executed
-
-    --debug     annotate program execution
-

Examples

Delete lines

# Delete two lines.
-echo -e 'aa\nbb\ncc\ndd' | sed '1d;3d'
-# bb
-# dd
-
-# Delete last ($) line.
-echo -e 'aa\nbb\ncc\ndd' | sed '$d'
-# aa
-# bb
-# cc
-
-# Delete range of lines.
-echo -e 'aa\nbb\ncc\ndd' | sed '1,3d'
-# dd
-
-# Delete lines matching pattern.
-echo -e 'aa\nbb\ncc\ndd' | sed '/bb/d'
-# aa
-# cc
-# dd
-
-# Delete lines NOT matching pattern.
-echo -e 'aa\nbb\ncc\ndd' | sed '/bb/!d'
-# bb
-

Insert lines

# Insert before line.
-echo -e 'aa\nbb' | sed '2iABC'
-# aa
-# ABC
-# bb
-
-# Insert after line.
-echo -e 'aa\nbb' | sed '2aABC'
-# aa
-# bb
-# ABC
-
-# Replace line.
-echo -e 'aa\nbb' | sed '2cABC'
-# aa
-# ABC
-
-# Insert before pattern match.
-echo -e 'aa\nbb' | sed '/bb/i 123'
-# aa
-# 123
-# bb
-

Substitute lines

# Substitute by regex.
-echo -e 'aafooaa\ncc' | sed 's/foo/MOOSE/'
-# aaMOOSEaa
-# cc
-

Multiple scripts

echo -e 'foo\nbar' | sed -e 's/foo/FOO/' -e 's/FOO/BAR/'
-# BAR
-# bar
-

Edit inplace through symlink

touch file
-ln -s file link
-ls -l link
-# lrwxrwxrwx 1 johannst johannst 4 Feb  7 23:02 link -> file
-
-sed -i --follow-symlinks '1iabc' link
-ls -l link
-# lrwxrwxrwx 1 johannst johannst 4 Feb  7 23:02 link -> file
-
-sed -i '1iabc' link
-ls -l link
-# -rw-r--r-- 1 johannst johannst 0 Feb  7 23:02 link
-

- -

Notes

sed(1)

Examples

Delete lines

Insert lines

Substitute lines

Multiple scripts

Edit inplace through symlink