How do I sort a colon or comma delimited file?

blackrhino

Also see: sort - sort lines of text files

       -t, --field-separator=SEP
              use SEP instead of non-blank to blank transition

       -k, --key=KEYDEF
              sort via a key; KEYDEF gives location and type

The syntax is as follows:
$ sort -t{delimiter} -k{n,m} filename

: - Delimiter.
n - The field.
m - The character position.

The delimiter in the demo is a colon but it can be a comma, space or any other delimiter.

Working on the following sample file contents:


pipewire:x:991:985:PipeWire System Daemon:/var/run/pipewire:/sbin/nologin
saslauth:x:990:76:Saslauthd user:/run/saslauthd:/sbin/nologin
dnsmasq:x:984:984:Dnsmasq DHCP and DNS server:/var/lib/dnsmasq:/sbin/nologin
radvd:x:75:75:radvd user:/:/sbin/nologin
clevis:x:983:982:Clevis Decryption Framework unprivileged user:/var/cache/clevis:/sbin/nologin
cockpit-ws:x:982:980:User for cockpit-ws:/nonexisting:/sbin/nologin
sssd:x:981:979:User for sssd:/:/sbin/nologin
colord:x:980:978:User for colord:/var/lib/colord:/sbin/nologin
gdm:x:42:42::/var/lib/gdm:/sbin/nologin
rpcuser:x:29:29:RPC Service User:/var/lib/nfs:/sbin/nologin
gnome-initial-setup:x:979:977::/run/gnome-initial-setup/:/sbin/nologin
sshd:x:74:74:Privilege-separated SSH:/var/empty/sshd:/sbin/nologin
avahi:x:70:70:Avahi mDNS/DNS-SD Stack:/var/run/avahi-daemon:/sbin/nologin
tcpdump:x:72:72::/:/sbin/nologin

To sort the file by UID.

$ sort -t: -k3n demo1
rpcuser:x:29:29:RPC Service User:/var/lib/nfs:/sbin/nologin
gdm:x:42:42::/var/lib/gdm:/sbin/nologin
avahi:x:70:70:Avahi mDNS/DNS-SD Stack:/var/run/avahi-daemon:/sbin/nologin
tcpdump:x:72:72::/:/sbin/nologin
sshd:x:74:74:Privilege-separated SSH:/var/empty/sshd:/sbin/nologin
radvd:x:75:75:radvd user:/:/sbin/nologin
gnome-initial-setup:x:979:977::/run/gnome-initial-setup/:/sbin/nologin
colord:x:980:978:User for colord:/var/lib/colord:/sbin/nologin
sssd:x:981:979:User for sssd:/:/sbin/nologin
cockpit-ws:x:982:980:User for cockpit-ws:/nonexisting:/sbin/nologin
clevis:x:983:982:Clevis Decryption Framework unprivileged user:/var/cache/clevis:/sbin/nologin
dnsmasq:x:984:984:Dnsmasq DHCP and DNS server:/var/lib/dnsmasq:/sbin/nologin
saslauth:x:990:76:Saslauthd user:/run/saslauthd:/sbin/nologin
pipewire:x:991:985:PipeWire System Daemon:/var/run/pipewire:/sbin/nologin

Sort by the Group ID and then the User ID. Demonstrates the use of using the key twice. The -n mean numerical.

$ sort -t: -k4n -k3n demo1

Perform a unique sort using the -u options. This performs a unique sort on the GID.

$ sort -t: -k4n -u demo1